<Page>

    AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON NOVEMBER 21, 2001
                                                      REGISTRATION NO. 333-66628

                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549

                                   -----------

                               AMENDMENT NO. 1 TO
                                    FORM S-3

                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933
                                   -----------

                                  EZENIA! INC.
             (Exact name of registrant as specified in its charter)

           DELAWARE                                  04-3114212
 (State or other jurisdiction of         (I.R.S. Employer identification No.)
  incorporation or organization)

                                 63 THIRD AVENUE
                         BURLINGTON, MASSACHUSETTS 01803
                                 (781) 229-2000
       (Address, including zip code, and telephone number, including area
               code, of registrant's principal executive offices)

                                   -----------

                                 KHOA D. NGUYEN
                           CHIEF EXECUTIVE OFFICER OF
                                  EZENIA! INC.
                                 63 Third Avenue
                         Burlington, Massachusetts 01803
                                 (781) 229-2000

            (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)

                                   -----------

                                 WITH COPIES TO:
                              DAVID L. ENGEL, ESQ.
                                Bingham Dana LLP
                               150 Federal Street
                                Boston, MA 02110
                                 (617) 951-8000

                                   -----------

        APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC:
   As soon as practicable after this Registration Statement becomes effective
   --------------------------------------------------------------------------


If the only securities being registered on this form are being offered pursuant
to dividend or interest reinvestment plans, please check the following box.
/ /

If any of the securities being registered on this form are to be offered
on a delayed or continuous basis pursuant to Rule 415 under the Securities Act
of 1933, check the following box. /X/

If this Form is filed to register additional securities for an offering pursuant
to Rule 462(b) under the Securities Act, please check the following box and list
the Securities Act registration statement number of the earlier effective
registration statement for the same offering. / /

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under
the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. / /

If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box. / /

         THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE
OR DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT
SHALL FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(a) OF
THE SECURITIES ACT OF 1933 OR UNTIL THE REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION 8(a),
MAY DETERMINE.
<Page>

INFORMATION CONTAINED HEREIN IS SUBJECT TO COMPLETION OR AMENDMENT. A
REGISTRATION STATEMENT RELATING TO THE SECURITIES HAS BEEN FILED WITH THE
SECURITIES AND EXCHANGE COMMISSION. THESE SECURITIES MAY NOT BE SOLD UNTIL THE
REGISTRATION STATEMENT FILED WITH THE SECURITIES AND EXCHANGE COMMISSION IS
EFFECTIVE. THIS PROSPECTUS IS NOT AN OFFER TO SELL THESE SECURITIES AND WE ARE
NOT SOLICITING AN OFFER TO BUY THESE SECURITIES IN ANY STATE WHERE THE OFFER OR
SALE IS NOT PERMITTED.

                   Subject to Completion, Dated August 2, 2001

                                   PROSPECTUS

                                  EZENIA! INC.

                                400,000 Shares of
                          Common Stock, $0.01 par value

         This prospectus of Ezenia! Inc., a Delaware corporation, relates to the
public offering of up to 400,000 shares of Ezenia!'s common stock, par value
$0.01 per share, by a certain stockholder of Ezenia!. More information is
provided in the section titled "Selling Stockholder." When used herein, the term
"selling stockholder" includes donees, transferees, pledgees and other
successors in interest. The shares have previously been issued by Ezenia!.

         Ezenia! will not receive any of the proceeds from the sale of the
shares by the selling stockholder. Ezenia!'s common stock is listed on the
Nasdaq National Market under the symbol "EZEN". On November 19, 2001, the
closing sale price of the common stock, as reported on the Nasdaq National
Market, was $0.66 per share.

         The selling stockholder may sell the shares in public or private
transactions, on or off the National Market System of the Nasdaq Stock Market,
at prevailing market prices, or at privately negotiated prices. The selling
stockholder may sell the shares directly to purchasers or through brokers or
dealers. Brokers or dealers may receive compensation in the form of discounts,
concessions or commissions from the selling stockholder. More information is
provided in the section titled "Plan of Distribution."

          INVESTING IN THE COMMON STOCK INVOLVES A HIGH DEGREE OF RISK.
                    SEE "RISK FACTORS," BEGINNING ON PAGE 2.

NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR DETERMINED WHETHER
THIS PROSPECTUS IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.

              The date of this Prospectus is ____________________.
<Page>

                                TABLE OF CONTENTS

<Table>
<Caption>
                                                                                               Page
                                                                                               ----

                                                                                              
Forward-Looking Statements...........................................................             1

Risk Factors.........................................................................             2

Where You Can Get More Information...................................................             7

Ezenia! Inc..........................................................................             8

Use of Proceeds......................................................................             8

Selling Stockholder..................................................................             8

Plan of Distribution.................................................................             9

Legal Matters........................................................................            10

Experts..............................................................................            10
</Table>



                           FORWARD-LOOKING STATEMENTS

         This prospectus includes forward-looking statements within the meaning
of Section 27A of the Securities Act of 1933 and Section 21E of the Securities
Exchange Act of 1934. Words such as "expect," "anticipate," "intend," "plan,"
"believe," "estimate," "likely," "will," "should" and variations of such words
and similar expressions are intended to identify such forward-looking
statements.

         These forward-looking statements are not guarantees of future
performance and are subject to risks, uncertainties and assumptions. The actual
results of Ezenia! could differ materially from those anticipated in the
forward-looking statements due to a number of factors, including those set forth
under "Risk Factors," in information incorporated by reference and elsewhere in
this prospectus. The factors set forth under "Risk Factors" and other cautionary
statements made in this prospectus should be read and understood as being
applicable to all related forward-looking statements wherever they appear in
this prospectus.

         The forward-looking statements contained in this prospectus represent
our judgment as of the date of this prospectus. Ezenia! cautions readers not to
place undue reliance on such statements. We undertake no obligation to update
publicly any forward-looking statements for any reason, even if new information
becomes available or other events occur in the future.


                                       1
<Page>

                                  RISK FACTORS

         BEFORE YOU INVEST IN OUR COMMON STOCK, YOU SHOULD BE AWARE THAT THERE
ARE VARIOUS RISKS, INCLUDING THOSE DESCRIBED BELOW, THAT COULD HAVE A MATERIAL
ADVERSE EFFECT ON OUR BUSINESS, INCLUDING OUR OPERATING RESULTS AND FINANCIAL
CONDITION. THE RISK FACTORS LISTED IN THIS SECTION, AS WELL AS ANY CAUTIONARY
LANGUAGE IN THIS PROSPECTUS, PROVIDE EXAMPLES OF RISKS, UNCERTAINTIES AND EVENTS
THAT MAY CAUSE OUR ACTUAL RESULTS TO DIFFER MATERIALLY FROM THE EXPECTATIONS WE
DESCRIBE IN OUR FORWARD-LOOKING STATEMENTS. YOU SHOULD CAREFULLY CONSIDER THESE
RISK FACTORS, TOGETHER WITH ALL OF THE OTHER INFORMATION INCLUDED IN OR
INCORPORATED BY REFERENCE INTO THIS PROSPECTUS, BEFORE YOU DECIDE WHETHER TO
PURCHASE SHARES OF OUR COMMON STOCK.

AS OF SEPTEMBER 30, 2001, WE HAD AN ACCUMULATED DEFICIT OF APPROXIMATELY
($30,551,000), FOR THE PAST 5 YEARS WE HAVE NOT ACHIEVED PROFITABILITY AND WE
MAY BECOME UNABLE TO FUND OPERATIONS IN THE NEAR FUTURE

         For the past 5 years we have not achieved profitability and, since
inception, have incurred significant net operating losses. At September 30,
2001, we had an accumulated deficit of approximately ($30,551,000). We expect
to continue to incur losses for the foreseeable future. Our ability to
continue as a going concern is dependent upon our ability to improve
operating margins considerably or to raise additional capital. There is
little likelihood of securing additional capital on reasonable terms, if at
all, in the near future. At September 30, 2001, the Company had cash, cash
equivalents and marketable securities of approximately $7.6 million, which
are regularly invested in short-term money market funds, government
securities, and commercial paper. The Company has committed an aggregate of
$3.1 million of this amount to cash collateralize two standby letters of
credit as security for a $2.0 million payment payable in January 2002 in
connection with the Company's acquisition of the InfoWorkSpace business and
$1.1 million which could become payable in January 2002 upon exercise of a
put option for 110,000 shares of the Company's common stock. In addition, in
connection with the put option, the Company may be required to purchase
another $2.9 million of its common stock in December 2002.

IF OUR NEWLY IMPLEMENTED RESTRUCTURING AND COST REDUCTION PLAN DOES NOT SUCCEED,
WE MAY NOT BE ABLE TO CONTINUE OPERATIONS IN THE NEAR FUTURE

         We recently implemented a restructuring and cost reduction plan to
align Company resources and expenses with our current revenue forecasts. This
plan involved a reduction in workforce of approximately one hundred employees,
including engineering, marketing and manufacturing employees in Burlington,
Massachusetts and salespeople in North America and Europe. When possible, we
also plan to close down our Burlington, Massachusetts facility and move our
office headquarters to a smaller, more cost efficient facility. There can be no
assurance that any actions implemented by the Company will reduce expenses or
increase revenue to the extent desired or that any reduction in expenses or
increase in revenue will materially extend the Company's ability to continue
operations.

OUR COMMON STOCK MAY BE DELISTED FROM THE NASDAQ NATIONAL MARKET, WHICH COULD
RESTRICT THE ABILITY OF OUR INVESTORS TO RESELL THEIR SHARES

         The Company's common stock is presently listed on the Nasdaq National
Market under the symbol EZEN. All companies listed on Nasdaq are required to
comply with certain continued listing standards, including maintaining a minimum
bid price for its common stock of at least $1.00. As of June 29, 2001, the
Company has not met this standard since its common stock has not traded at a
minimum bid price of at least $1.00 over the previous 30 consecutive trading
days. On September 27, 2001, Nasdaq announced that it would suspend enforcement
of its continued listing standards through January 2, 2002. After such date, if
the Company fails to meet the required $1.00 minimum bid price for its common
stock for at least 30 consecutive trading days, or if the Company is otherwise
not in compliance with Nasdaq rules, the Company's common stock will be delisted
from Nasdaq unless the Company successfully appeals the delisting determination.
There can be no assurance that the Company's common stock will meet the required
$1.00 minimum bid price at any time in the future or that any appeal by the
Company of a delisting determination would be successful. There can therefore be
no assurance that the Company's common stock will continue to be listed on
Nasdaq in the future. In the event that the Company's common stock is delisted
from Nasdaq, the market value and liquidity of the Company's common stock could
be materially adversely affected.

INVESTORS MAY HAVE DIFFICULTY SELLING SHARES OF OUR COMMON STOCK IF OUR SHARES
BECOME SUBJECT TO THE "PENNY STOCK" REGULATIONS

         If the Company's common stock is delisted from trading on the Nasdaq
National Market and the trading price of the common stock is less than $5.00 per
share, trading in the common stock would be subject to the requirements of Rule
15g-9 under the Securities Exchange Act of 1934. Under this rule, broker/dealers
who recommend low-priced securities to persons other than established customers
and accredited investors must satisfy


                                       2
<Page>

special sales practice requirements. The broker/dealer must make an
individualized written suitability determination for the purchaser, provide the
purchaser with a disclosure schedule explaining the penny stock market and its
risks and receive the purchaser's written consent to the transaction prior to
the sale. These requirements limit the ability of broker/dealers to sell penny
stocks. Also, because of the extra requirements, many broker/dealers are
unwilling to sell penny stocks at all. As a result, if the Company's common
stock becomes subject to the penny stock regulations, it may become difficult
for investors to sell shares of the Company's common stock.

IF OUR ENCOUNTER AND INFOWORKSPACE REAL-TIME COLLABORATION PRODUCTS DO NOT
ACHIEVE MARKET ACCEPTANCE, WE WILL NOT BE ABLE TO GENERATE THE REVENUE NECESSARY
TO SUPPORT OUR BUSINESS

         As we continue to shift our focus away from traditional ISDN-based
videoconferencing products, we are becoming increasingly dependent on revenue
from sales of IP and Internet based videoconferencing products with real-time
collaboration capabilities. Sales from these products accounted for
approximately 50% of our revenue in the third quarter of 2001. Therefore, the
Company's success depends, to a significant extent, on the acceptance and the
rate of adoption of IP and Internet based collaboration products, in general,
and Encounter and InfoWorkSpace products in particular. There is inadequate
experience to predict whether real-time collaboration products will ultimately
be accepted by the market. Even if the Company demonstrates the efficiency,
effectiveness and interoperability of its Internet based collaboration products,
videoconference users may continue to use traditional ISDN-based products simply
because such products are already so widely accepted and are based on
established technologies. There can be no assurance that any of the markets for
the Company's products will develop to the extent, in the manner, or at the rate
anticipated by the Company. In addition, future prices the Company is able to
obtain for its products may decrease as a result of new product introductions by
others, price competition, technological change or other factors.

WE DEPEND ON A SMALL NUMBER OF MAJOR CUSTOMERS FOR THE MAJORITY OF OUR REVENUE
AND IF ONE OR MORE OF OUR MAJOR CUSTOMERS WERE TO SIGNIFICANTLY REDUCE CURRENT
ORDER LEVELS WE MAY BE UNABLE TO GENERATE SUFFICIENT SALES TO CONTINUE OUR
BUSINESS

         Historically, sales to a relatively small number of customers have
accounted for a significant portion of our revenue. In the third quarter of
2001, six customers have accounted for 57% of our revenue. The Company believes
that its dependence on a relatively small number of end-users, including those
in the defense and intelligence sectors of the federal government, will continue
during 2001 and 2002. This concentration of customers may cause revenues and
operating results to fluctuate from quarter to quarter based on major customers'
requirements and the timing of their orders. Our agreements with our customers
generally do not include minimum purchase commitments or exclusivity
arrangements. Our operating results could be materially and adversely affected
if any present or future major customer were to choose to reduce its level of
orders, were to change to another vendor for purchases of a similar product,
were to combine their operations with another organization that had an
established relationship with another vendor for purchases of a similar product,
were to experience financial, operational or other difficulties or were to delay
paying or fail to pay amounts due.

WE FACE COMPETITION FROM LARGE, WELL ESTABLISHED MANUFACTURERS OF MULTIMEDIA
COLLABORATION PRODUCTS WITH SIGNIFICANT RESOURCES, WHICH MAY RESULT IN DECREASED
DEMAND FOR OUR PRODUCTS AND SERVICES

         The market for multimedia collaboration products is highly competitive.
We consider our primary competitors to be Polycom, RADvision and Lucent. We also
face competition or potential competition from companies that provide similar,
but not directly competing products, such as FVC, Centra, WebEx and IBM Lotus,
or companies that could expand their offerings and develop a product similar to
ours such as Microsoft. Many of these companies, as well as other current and
potential competitors, have substantially greater financial, technical, and
sales and marketing resources than the Company. If we are unable to convince
companies with collaboration and videoconferencing needs to adopt the Encounter
and InfoWorkSpace collaboration products over the current technologies marketed
by our competitors, our financial results will suffer, through price reductions
and loss of market share.

         The principal competitive factors in the market for multimedia
collaboration are, and should continue to be, breadth of capabilities,
demonstrated interoperability, price, performance, network management
capabilities,


                                       3
<Page>

reliability, customer support and security. We plan to compete by offering
collaboration and enterprise products with a broad range of capabilities and
high performance. However, we cannot be certain that potential customers will
be attracted to our products, especially if our competitors were to invest
substantially more money into their products and technology.

BECAUSE THE CONFERENCING INDUSTRY IS CHARACTERIZED BY RAPID TECHNOLOGICAL
CHANGE, IF WE FAIL TO CONTINUOUSLY ENHANCE OUR TECHNOLOGY AND PRODUCTS OUR
BUSINESS COULD SUFFER

         The market for our products is characterized by rapidly changing
technology, evolving industry standards, emerging network architectures and
frequent new product introductions. The adoption rate of new technologies and
products may adversely impact near-term growth of the conferencing market as
users evaluate the alternatives. We have invested, and currently plan to
continue to invest, in software development and products incorporating certain
of these new technologies. Many other companies are also developing products
incorporating these new technologies that are competitive with Ezenia!'s current
and future offerings. Ezenia!'s success will depend, in part, upon the
following:

          o    our ability through continued investments to maintain
               technological competitiveness

          o    our ability to enhance and expand our existing product offerings

          o    our ability to select and develop in a timely manner new products
               that achieve market acceptance

         If we are unable, for technical or other reasons, to develop and
introduce new services or enhancements of existing services in a timely manner
in response to changing market conditions or customer requirements, or if new
services do not achieve market acceptance, our business, financial condition and
results of operations could be materially and adversely affected.

WE HAVE LIMITED EXPERIENCE IN MARKETING AND SELLING OUR INFOWORKSPACE PRODUCTS
TO THE COMMERCIAL SECTOR AND MAY ENCOUNTER PROBLEMS OR DELAYS THAT COULD RESULT
IN LOSS OF REVENUE

         Prior to our purchase of the InfoWorkSpace products and technology in
March 2001, these products were developed by General Dynamics for use by the
federal government. We have limited experience in marketing and selling
InfoWorkSpace products for use by the commercial sector. We will face
significant challenges and risks in building and managing our sales and
marketing team, including managing geographically dispersed sales efforts and
adequately training our sales people in the use of the InfoWorkSpace products.
To succeed in the implementation of our business strategy, our management team
must rapidly execute our sales and marketing strategy, while continuing our
research and development activities and managing anticipated growth by
implementing effective planning. If our development and marketing efforts fail,
our ability to generate revenues will be limited and our reputation in the
marketplace may be harmed.

IF WE DO NOT SUCCESSFULLY INTEGRATE THE INFOWORKSPACE OPERATIONS, OUR BUSINESS
COULD SUFFER

         The Company acquired InfoWorkSpace with the expectation that the
transaction would result in certain benefits, including, among other things,
benefits relating to expanded and complementary product offerings, enhanced
revenues, increased market opportunity, new technology and the addition of
engineering personnel. Achieving the benefits of the acquisition will depend in
large part on the integration of our technology, operations and personnel in a
timely and efficient manner. If we are unable to successfully integrate
InfoWorkSpace management and developers, who work in Colorado and the
Washington, D.C. area, with our existing operations, based in Massachusetts, the
Company might lose market opportunities and key employees and direct
management's attention away from other matters concerning the operation of our
business.

OUR STOCK PRICE HAS BEEN EXTREMELY VOLATILE AND MAY CONTINUE TO BE SO IN THE
FUTURE

         Our shares have traded at prices between $0.22 and $4.375 per share
in the past twelve months. Additionally, the market for shares in
technology-related companies is subject to extreme price and volume
fluctuations. Market reaction to information relating to our Company, as well
as broad fluctuations in market prices

                                       4
<Page>

of shares in similarly situated companies, may materially and adversely affect
the price of our common stock. The price of our shares may continue to be
volatile in the future, and may be affected by a number of factors, including:

          o    actual or perceived likelihood of our inability to continue
               funding operations

          o    actual or anticipated fluctuations in our operating results

          o    changes in investors' and securities analysts' expectations as to
               our future financial performance or changes in financial
               estimates of securities analysts

          o    announcement of new products or product enhancements by us or our
               competitors

          o    technological innovations by us or our competitors

          o    the operating and stock price performance of comparable companies

WE DEPEND ON OUR KEY PERSONNEL TO IMPLEMENT OUR BUSINESS STRATEGY

         Due in part to our recent restructuring and cost reduction plan and
acquisition of InfoWorkSpace, the Company is at a critical stage in its
business, product and administrative development and it would be extremely
disruptive if we were to lose members of our management team in the near term.
Our success depends, to a significant degree, upon the continuing contributions
of our key management, sales, marketing and research and development personnel,
many of whom would be difficult to replace, including Khoa Nguyen, the Company's
Chief Executive Officer. We do not have employment contracts with our key
personnel other than Khoa Nguyen. The Company believes that its future success
will depend in large part upon its ability to attract and retain such key
employees.

WE MAY NOT BE ABLE TO PROTECT OUR INTELLECTUAL PROPERTY AND PROPRIETARY RIGHTS

         Ezenia!'s success and ability to compete, depends, to a large extent,
on our ability to protect our proprietary technology. In addition to our patents
and patent applications relating to our products, we rely primarily on a
combination of contractual rights, trade secrets and copyrights to protect our
intellectual property rights.

         Legal standards relating to the protection of intellectual property
rights in Internet-related industries are uncertain and still evolving. As a
result, the future viability or value of our intellectual property rights, as
well as those of other companies that conduct business over the Internet, is
unknown. Despite our efforts to protect our proprietary rights, unauthorized
parties may attempt to copy aspects of our technology or obtain and use
information that we regard as proprietary. Policing unauthorized use of our
proprietary rights is difficult. In addition, litigation may be necessary in the
future to enforce our intellectual property rights, to protect our trade secrets
or trademarks or to determine the validity and scope of the proprietary rights
of others. Litigation might result in substantial costs and diversion of
resources and management attention. Any infringement or misappropriation of our
proprietary rights and the related costs of enforcing those rights could have a
material adverse effect on our business, financial condition and results of
operations.

WE MAY INFRINGE UPON OTHER PARTIES' PROPRIETARY RIGHTS

         Our business activities may infringe upon the proprietary rights of
others and other parties may assert infringement claims against us. Moreover,
from time to time, third parties may allege infringement by us or our strategic
partners on their trademarks, service marks and other intellectual property
rights. Such claims and any resultant litigation could subject us to significant
liability for damages, might result in invalidation of our proprietary rights
and, even if not meritorious, could result in substantial costs and diversion of
resources and management attention and have a material adverse effect on our
business, financial condition and results of operations.



                                       5
<Page>

PROVISIONS OF OUR GOVERNING DOCUMENTS AND DELAWARE LAW COULD DISCOURAGE
ACQUISITION PROPOSALS OR DELAY A CHANGE IN CONTROL OF EZENIA!

         Our certificate of incorporation and by-laws contain anti-takeover
provisions, including those listed below, that could make it more difficult for
a third party to acquire control of us, even if that change in control would be
beneficial to shareholders:

         o     our board of directors has the authority to issue common stock
               and preferred stock and to determine the price, rights and
               preferences of any new series of preferred stock without
               shareholder approval

         o     our board of directors is divided into three classes, each
               serving three-year terms

         o     supermajority voting is required to amend key provisions of our
               certificate of incorporation and by-laws

         o     there are limitations on who can call special meetings of
               shareholders

         o     shareholders may not take action by written consent

         o     advance notice is required for nominations of directors and for
               shareholder proposals

         In addition, provisions of Delaware law and our stock option plans may
also discourage, delay or prevent a change of control of Ezenia! or unsolicited
acquisition proposals.


                                       6
<Page>

                       WHERE YOU CAN GET MORE INFORMATION

         Ezenia! is subject to the reporting requirements of the Securities
Exchange Act of 1934 and files annual, quarterly and current reports, proxy
statements and other information with the SEC. You may read and copy these
reports, proxy statements and other information at the SEC's public reference
facilities at 450 Fifth Street, N.W., Washington, D.C. 20549. You can request
copies of these documents by writing to the SEC and paying a fee for the copying
cost. Please call the SEC at 1-800-SEC-0330 for more information about the
operation of the public reference facilities. SEC filings are also available at
the SEC's Web site at http://www.sec.gov.

         The SEC allows us to "incorporate by reference" information that we
file with them. Incorporation by reference allows us to disclose important
information to you by referring you to those other documents. The information
incorporated by reference is an important part of this prospectus, and
information that we file later with the SEC will automatically update and
supersede this information.

         We incorporate by reference the documents listed below, and any future
filings we will make with the SEC under Section 13(a), 13(c), 14 or 15(d) of the
Securities Exchange Act of 1934 prior to termination of the offering:

         o     Annual Report on Form 10-K for the fiscal year ended December 31,
               2000, filed on March 12, 2001.

         o     Current Report on Form 8-K, filed on April 11, 2001, as amended
               on June 11, 2001.

         o     Quarterly Report on Form 10-Q for the fiscal quarters ended March
               31, 2001, June 30, 2001 and September 30, 2001.

         o     The description of the common stock contained in the Registration
               Statement on Form S-1 of Ezenia! filed on April 12, 1995 with the
               SEC, as amended.

         You may request a copy of these filings at no cost, by writing or
telephoning us at the following address:

                                      Ezenia! Inc.
                                      63 Third Avenue
                                      Burlington, Massachusetts  01803
                                      (781) 229-2000
                                      Attn:  Laura M. Alessio, Manager,
                                      Investor Relations

         This prospectus is part of a registration statement we filed with the
SEC. You should rely only on the information incorporated by reference or
provided in this prospectus. No one else is authorized to provide you with
different information. We are not making an offer of these securities in any
state where the offer is not permitted. You should not assume that the
information in this prospectus is accurate as of any date other than the date on
the front of this document.


                                       7
<Page>

                                  EZENIA! INC.

         Ezenia! Inc. is a leading global provider of real-time collaboration
solutions for corporate networks and eBusiness. Founded in 1991, Ezenia!
develops and markets products that enable organizations to provide high-quality
group communication and collaboration capabilities to commercial, consumer and
institutional users. We believe that our products are used by over 50% of those
companies currently using conferencing and collaboration solutions. Ezenia!'s
products allow individuals and groups that are geographically distant from each
other to interact and share information in a natural, spontaneous way --
voice-to-voice, face-to-face, flexibly and in real-time - via a wide range of
networks. Using our products, disparately located individuals can interact
through a natural meeting experience, allowing groups to work together
effectively and disseminate vital information quickly. Ezenia!'s products enable
seamless connectivity across a wide range of networks including LANs, intranets,
the Internet, ISDN, ATM and frame relay.

         We believe that we offer one of the most comprehensive sets of
collaborative products available. For example, between our Encounter and
InfoWorkSpace products, we enable videoconferencing, voice communication,
instant messaging, white boarding and virtual workspaces. Furthermore, because
the Encounter products include a software only solution and a configurable
hardware solution, in contrast to the products offered by our competitors, the
Encounter family of products can be deployed easily at small sites or in
locations with a large number of users.

          Ezenia! sells its products worldwide through leading resellers,
integrators and remarketers of collaboration, videoconferencing and networking
solutions, including PictureTel, VTEL, Sony and General Dynamics, each of which
is widely acknowledged as a leader in its field. Ezenia! also sells directly to
end users of collaboration products and to providers of conferencing services.


                                 USE OF PROCEEDS

         The selling stockholder will receive the net proceeds from any sales of
its shares of common stock offered pursuant to this Registration Statement.
Ezenia! will not receive any proceeds from these sales.


                               SELLING STOCKHOLDER

         On March 27, 2001, General Dynamics Government Systems Corporation
acquired 400,000 shares of Ezenia!'s common stock in a transaction exempt
from the registration requirements of the Securities Act of 1933, in
connection with an asset purchase agreement, dated as of December 28, 2000.
Pursuant to the asset purchase agreement, Ezenia! purchased all of the
operating assets and intellectual property used by the Electronic Systems
division of General Dynamics Government Systems Corporation in the conduct of
its InfoWorkSpace product and technology business in exchange for $17,000,000
in cash, $2,000,000 of which is to be paid January 2002, and 400,000 shares
of Ezenia!'s common stock. Pursuant to that certain put agreement, as
amended, entered into in connection with the asset purchase agreement, the
400,000 shares are accompanied by an option allowing General Dynamics
Government Systems Corporation to require Ezenia! to repurchase 110,000
shares beginning January 4, 2002 and expiring February 3, 2002, and the
balance of 290,000 shares beginning December 1, 2002 and expiring December
31, 2002, at a price of $10 per share. The "put" right otherwise expires at
such time as the last reported closing price of the common stock as reported
on the Nasdaq National Market has been equal to or greater than $11.00
per-share for fifteen (15) consecutive trading days.

         Pursuant to the asset purchase agreement, Ezenia! agreed to file with
the Securities and Exchange Commission a registration statement, of which this
prospectus is a part, with respect to the resale of the 400,000 shares issued to
General Dynamics Government Systems Corporation. Ezenia! has committed to keep
the registration statement effective until the earlier of (i) March 27, 2003 or
(ii) such times as all of the shares have been resold.

         Our registration of the shares does not necessarily mean that General
Dynamics Government Systems Corporation will sell all or any of the shares. The
information provided in the table below with respect to General Dynamics
Government Systems Corporation has been obtained from General Dynamics
Government Systems Corporation. General Dynamics Government Systems Corporation
has not had any position, office or other material


                                       8
<Page>

relationship with Ezenia! or any of its affiliates. Because General Dynamics
Government Systems Corporation may sell all or some or none of the shares, only
an estimate (assuming the sale of all of the shares) can be given as to the
number of shares of common stock that will be owned by General Dynamics
Government Systems Corporation after this offering.

         As of November 9, 2001, there were 13,741,880 shares of Ezenia!'s
common stock issued and outstanding.

<Table>
<Caption>
                                            Shares Owned                                     Shares to be Owned
Name of Selling Stockholder              Prior to Offering           Shares Offered            After Offering
- -------------------------------         -------------------         ----------------        --------------------
                                                                                            
General Dynamics Government
Systems Corporation                           400,000                   400,000                      0
</Table>

        Kenneth C. Dahlberg, President, and Michael J. Mancuso, Vice President
and Treasurer, of General Dynamics Government Systems Corporation exercise
voting power and investment power over the shares of common stock offered
pursuant to this Registration Statement.

                              PLAN OF DISTRIBUTION

         The shares may be sold from time to time by General Dynamics Government
Systems Corporation or its donees, pledgees, transferees and other successors in
interest in one or more transactions at fixed prices, at market prices at the
time of sale, at varying prices determined at the time of sale or at negotiated
prices. The shares may be sold in one or more of the following transactions:

          --   on any national securities exchange or quotation service on which
               the common stock may be listed or quoted at the time of sale,
               including the Nasdaq National Stock Market,

          --   in the over-the-counter market,

          --   in private transactions,

          --   through options, or

          --   a combination of any of the above transactions.

         Ezenia! reserves the right to terminate the registration statement of
which this prospectus forms a part at any time after March 17, 2003.

         At the time a particular offering of the shares is made, a supplement
to this prospectus, if required, will be distributed which will set forth the
aggregate number and type of shares being offered and the terms of the offering,
including the name or names of any underwriters, brokers/dealers or agents, any
discounts, commissions and other terms constituting compensation from General
Dynamics Government Systems Corporation and any discounts, commissions or
concessions allowed or reallowed to be paid to broker/dealers.

         The shares may be sold from time to time directly by General Dynamics
Government Systems Corporation. Alternatively, General Dynamics Government
Systems Corporation may from time to time sell or distribute the shares to or
through broker/dealers or agents. General Dynamics Government Systems
Corporation and any broker/dealers or agents that participate in the
distribution of the shares may be deemed to be "underwriters" within the meaning
of the Securities Act of 1933. Any profits on the resale of the shares and any
compensation received by any broker/dealer or agent may be deemed to be
underwriting discounts and commissions under the Securities Act of 1933.

         To comply with the securities laws of certain jurisdictions, if
applicable, the shares must be offered or sold only through registered or
licensed brokers or dealers. In addition, in certain jurisdictions, the shares
may not be offered or sold unless they have been registered or qualified for
sale or an exemption is available and complied with.

         Under applicable rules and regulations under the Securities Exchange
Act of 1934, any person engaged in a distribution of the shares offered hereby
may not simultaneously engage in market-making activities with respect to our
common stock for a specified period prior to the start of the distribution. In
addition, General Dynamics


                                       9
<Page>

Government Systems Corporation and any other person participating in a
distribution will be subject to the Securities Exchange Act and the rules and
regulations promulgated under the Securities Exchange Act, including Regulation
M, which may limit the timing of purchases and sales of the shares by General
Dynamics Government Systems Corporation or any such other person. These factors
may affect the marketability of the shares and the ability of brokers or dealers
to engage in market-making activities.

         We shall pay all expenses of this registration. These expenses include
the SEC's filing fees and any fees under state securities or "blue sky" laws.
General Dynamics Government Systems Corporation will pay all underwriting
discounts and selling commissions, if any.

                                  LEGAL MATTERS

         The validity of the shares being offered by this prospectus and other
legal matters concerning this offering will be passed upon for us by Bingham
Dana LLP, Boston, Massachusetts.

                                     EXPERTS

         The consolidated financial statements of Ezenia! Inc. appearing in
Ezenia! Inc.'s Annual Report (Form 10-K) for the year ended December 31, 2000,
have been audited by Ernst & Young LLP, independent auditors, as set forth in
their report thereon included therein and incorporated herein by reference. Such
consolidated financial statements are incorporated herein by reference in
reliance upon such report given upon the authority of such firm as experts in
accounting and auditing.

        The financial statements of InfoWorkSpace (a Product Line of the
Electronic Systems Division of General Dynamics Government Systems
Corporation) incorporated by reference in this registration statement have
been audited by Arthur Andersen LLP, independent public accountants, as
indicated in their report with respect thereto, and are included herein in
reliance upon the authority of said firm as experts in giving said report.

                                       10
<Page>

================================================================================

WE HAVE NOT AUTHORIZED ANY DEALER, SALESPERSON OR OTHER PERSON TO GIVE ANY
INFORMATION OR TO MAKE ANY REPRESENTATIONS NOT CONTAINED IN THIS PROSPECTUS OR
ANY PROSPECTUS SUPPLEMENT. YOU MUST NOT RELY ON ANY UNAUTHORIZED INFORMATION.
NEITHER THIS PROSPECTUS NOR ANY PROSPECTUS SUPPLEMENT IS AN OFFER TO SELL OR A
SOLICITATION OF AN OFFER TO BUY ANY OF THESE SECURITIES IN ANY JURISDICTION
WHERE AN OFFER OR SOLICITATION IS NOT PERMITTED. NO SALE MADE PURSUANT TO THIS
PROSPECTUS SHALL, UNDER ANY CIRCUMSTANCES, CREATE ANY IMPLICATION THAT THERE HAS
NOT BEEN ANY CHANGE IN THE AFFAIRS OF EZENIA! SINCE THE DATE OF THIS PROSPECTUS.

================================================================================



                                 400,000 SHARES

                                  EZENIA! INC.

                                  COMMON STOCK

                               -------------------

                                   PROSPECTUS

                              ---------- ---, ----

                               -------------------







================================================================================
<Page>

                                     PART II
                     INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 14.   OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION

         The expenses in connection with the issuance and distribution of the
securities being registered are set forth in the following table (all amounts
except the registration fee and the listing fee are estimated):

<Table>
                                                                                          
SEC Registration Fee.......................................................................  $    26.50
Legal Fees and Expenses....................................................................  $25,000.00
Accountants' Fees and Expenses.............................................................  $10,000.00
Miscellaneous Costs........................................................................  $ 3,973.50
                                                                                             -----------
      Total................................................................................  $39,000.00
</Table>


         All expenses in connection with the issuance and distribution of the
securities being offered shall be borne by Ezenia!.

ITEM 15.   INDEMNIFICATION OF DIRECTORS AND OFFICERS

         Section 145 of the Delaware General Corporation Law empowers a Delaware
corporation to indemnify its officers and directors and certain other persons to
the extent and under the circumstances set forth therein.

         Ezenia!'s Amended and Restated Certificate of Incorporation and Amended
and Restated By-Laws provide for advancement of expenses and indemnification of
officers and directors of the Registrant and certain other persons against
liabilities and expenses incurred by any of them in certain stated proceedings
and under certain stated conditions to the fullest extent permissible under
Delaware law.

ITEM 16.   EXHIBITS

         *3.1(a)  Certificate of Amendment to Certificate of Incorporation of
                  the Registrant. (Incorporated by reference to Exhibit 4.1 to
                  the Registrant's Registration Statement on From S-8,
                  Registration No. 333-44984, filed August 31, 2000.)

         *3.1(b)  Certificate of Incorporation of the Registrant. (Incorporated
                  by reference to Exhibit 3.1 to the Registrant's Registration
                  Statement on Form S-1, Registration No. 33-91132, filed April
                  12, 1995.)

         *3.2     Amended and Restated By-Laws of the Registrant. (Incorporated
                  by reference to Exhibit 3.2 to the Registrant's Registration
                  Statement on Form S-1, Registration No. 33-91132, filed April
                  12, 1995.)

         *4.1     Asset Purchase Agreement, dated as of December 28, 2000,
                  between the Registrant and General Dynamics Government Systems
                  Corporation. (Incorporated by reference to Exhibit 10.20 to
                  the Registrant's Annual Report on Form 10-K, File No 0-25882,
                  filed March 12, 2001.)

         *5       Opinion of Bingham Dana LLP.

         *23.1    Consent of Bingham Dana LLP.

         23.2     Consent of Ernst & Young LLP.

         23.3     Consent of Arthur Andersen LLP.

         *24.1    Power of Attorney.

*Previously filed with the Registrant's Registration Statement on Form S-3,
Registration No. 333-66628, filed on August 2, 2001.


                                     - 1 -
<Page>

ITEM 17.   UNDERTAKINGS

         The undersigned registrant hereby undertakes:

                           (1) To file, during any period in which offers or
                  sales are being made pursuant to this registration statement,
                  a post-effective amendment to this registration statement to
                  include any material information with respect to the plan of
                  distribution not previously disclosed in this registration
                  statement or any material change to such information in this
                  registration statement;

                           (2) That, for the purpose of determining any
                  liability under the Securities Act of 1933, each such
                  post-effective amendment shall be deemed to be a new
                  registration statement relating to the securities offered
                  therein, and the offering of such securities at that time
                  shall be deemed to be the initial bona fide offering thereof.

                           (3) To remove from registration by means of a
                  post-effective amendment any of the securities being
                  registered which remain unsold at the termination of the
                  offering.

         The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
registrant's annual report pursuant to Section 13(a) or 15(d) of the Securities
Exchange Act of 1934 (and, where applicable, each filing of an employee benefit
plan's annual report pursuant to Section 15(d) of the Securities Exchange Act of
1934) that is incorporated by reference in the registration statement shall be
deemed to be a new registration statement relating to the securities offered
therein, and the offering of such securities at that time shall be deemed to be
the initial BONA FIDE offering thereof.

         Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors, officers and controlling persons of
the Registrant pursuant to the foregoing provisions described in Item 15 above,
or otherwise, the Registrant has been advised that in the opinion of the
Securities and Exchange Commission such indemnification is against public policy
as expressed in the Securities Act and is, therefore, unenforceable. In the
event that a claim for indemnification against such liabilities (other than the
payment by the Registrant of expenses incurred or paid by a director, officer or
controlling person of the Registrant in the successful defense of any action,
suit or proceeding) is asserted by such director, officer or controlling person
in connection with the securities being registered, the Registrant will, unless
in the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction the question whether
such indemnification by it is against public policy as expressed in the
Securities Act and will be governed by the final adjudication of such issue.


                                     - 2 -
<Page>

                                   SIGNATURES

         Pursuant to the requirements of the Securities Act of 1933, as amended,
the registrant, Ezenia! Inc., certifies that it has reasonable grounds to
believe that it meets all of the requirements for filing on Form S-3 and has
duly caused this Amendment No. 1 to the Registration Statement to be signed on
its behalf by the undersigned, thereunto duly authorized, in the Town of
Burlington and the Commonwealth of Massachusetts, on this 21st day of November,
2001.

                          EZENIA! INC.

                          By:  /s/ Stephen G. Bassett
                               -----------------------------------
                               Stephen G. Bassett
                               CHIEF FINANCIAL OFFICER

         Pursuant to the requirements of the Securities Act of 1933, this
Amendment No. 1 to the Registration Statement has been signed below by the
following persons in the capacities and on the dates indicated:

<Table>
<Caption>
SIGNATURE                               TITLE                                                 DATE
- ---------                               -----                                                 ----

                                                                                        
/s/ Khoa D. Nguyen                      Chairman of the Board of Directors, President and     November 21, 2001
- ---------------------------------       Chief Executive Officer (principal executive
Khoa D. Nguyen                          officer)


/s/ Stephen G. Bassett                  Chief Financial Officer (principal financial and      November 21, 2001
- ---------------------------------       accounting officer)
Stephen G. Bassett

- ---------------------------------       Director
William E. Foster

/s/ John F. Keane, Jr.*                 Director                                              November 21, 2001
- ---------------------------------
John F. Keane, Jr.

/s/ John A. McMullen*                   Director                                              November 21, 2001
- ---------------------------------
John A. McMullen

/s/ Roy G. Perry*                       Director                                              November 21, 2001
- ---------------------------------
Roy G. Perry

*By:   /s/ Stephen G. Bassett
       ---------------------------------
         Stephen G. Bassett
         ATTORNEY-IN-FACT
</Table>


                                     - 3 -
<Page>
                                  EXHIBIT INDEX

EXHIBITS
- --------

*3.1(a)  Certificate of Amendment to Certificate of Incorporation of the
         Registrant. (Incorporated by reference to Exhibit 4.1 to the
         Registrant's Registration Statement on From S-8, Registration No.
         333-44984, filed August 31, 2000.)

*3.1(b)  Certificate of Incorporation of the Registrant. (Incorporated by
         reference to Exhibit 3.1 to the Registrant's Registration Statement on
         Form S-1, Registration No. 33-91132, filed April 12, 1995.)

*3.2     Amended and Restated By-Laws of the Registrant. (Incorporated by
         reference to Exhibit 3.2 to the Registrant's Registration Statement on
         Form S-1, Registration No. 33-91132, filed April 12, 1995.)

*4.1     Asset Purchase Agreement, dated as of December 28, 2000, between the
         Registrant and General Dynamics Government Systems Corporation.
         (Incorporated by reference to Exhibit 10.20 to the Registrant's Annual
         Report on Form 10-K, File No 0-25882, filed March 12, 2001.)

*5       Opinion of Bingham Dana LLP.

*23.1    Consent of Bingham Dana LLP.

23.2     Consent of Ernst & Young LLP.

23.3     Consent of Arthur Andersen LLP.

*24.1    Power of Attorney.


*Previously filed with the Registrant's Registration Statement on Form S-3,
Registration No. 333-66628, filed on August 2, 2001.


                                     - 4 -