March 24, 1995


Mr. Don O'Connor
64 Tallmadge Ave
Chatham, NJ  07928


Dear Don:


We are very pleased to offer you the position of Vice President Customer 
Support with Applied Digital Access, Inc., reporting to Pete Savage, Chief 
Executive Officer.  We are very excited that you will be joining the ADA team 
as a regular full-time employee. Your compensation will be $5,208.33, paid 
semimonthly (equivalent to $125,000.00 on an annualized basis).  In addition, 
you will receive the other benefits afforded to all regular full-time 
employees of ADA.  These include two weeks paid vacation, partially paid 
health insurance coverage through participation in ADA's Section 125 
Cafeteria Plan, the opportunity to participate in a 401(k) plan, and the 
opportunity to participate in ADA's Stock Purchase Plan.

When you report on board as a regular full-time employee of ADA, we will pay 
to you a one-time bonus of $10,000.

As Vice President Customer Support, you will be an officer of the Company and 
will participate in the Management Team Incentive Compensation Plan.  This 
plan provides for a cash payment of 30% of base salary at plan as approved by 
the Compensation Committee of the Board of Directors.

As a key part of your compensation package, we will recommend to the Board of 
Directors that you be granted an option to purchase 50,000 shares of ADA 
common stock in accordance with ADA's Incentive Stock Option Plan.  This 
stock will vest over a four-year period, with one-fourth fully vested at the 
end of your first twelve months of employment at ADA and the remainder 
vesting monthly thereafter.  The exercise price of shares granted under ADA's 
Incentive Stock Option Plan will be determined at the time your option is 
granted by ADA's Board of Directors.

To assist you in relocating to San Diego, we will provide reimbursement for 
up to $50,000 for relocation and interim living expenses as incurred.  This 
amount will be subject to Federal and State withholding regulations.  We will 
reimburse you for the those taxes to be paid up to a maximum of $20,000.  If 
you leave ADA before the end of two years from your date of hire, this 
relocation assistance will be deemed subject to prorated repayment based on 
the number of months you work at ADA.

We will guarantee, upon acceptance of this offer of employment, that you will 
be employed by ADA for a minimum of twelve months.  Thereafter, you will be 
entitled to three months salary as severance in the 



event of your involuntary separation of employment from ADA, or the severance 
arrangement in force, whichever is greater.

Except as noted above, employment with Applied Digital Access is not for a 
specific term and can be terminated by you or by ADA at any time for any 
reason, with or without cause.  Any contrary representations which may have  
been made to you are superseded by this offer.  Any modification to this 
at-will term of your employment must be in writing and signed by you and by 
ADA's President.

ADA is committed to a drug-free workplace and has a zero-tolerance drug 
policy. Illegal possession or use of drugs of any kind, at any time, on or 
off company premises within or outside of working hours may result in 
immediate dismissal. 

Smoking is not permitted on company property or at any company off-premises 
events.

This offer is contingent on your executing the enclosed Proprietary 
Information and Inventions Agreement and providing ADA with the legally 
required proof of your identity and authorization to work in the United 
States. Please sign both copies of this letter, retain one copy for your 
files, and return the second copy to us as soon as possible.  Don, we are 
delighted to have you join our team.   We look forward to working with you, 
and to enjoying the success our team will realize together.

Sincerely,


      /s/ Peter P. Savage                         /s/ Richard W. Carter
- -------------------------                         ----------------------
          Peter P. Savage                          Richard W. Carter
          President - CEO                         Vice President, Finance

Please indicate your acceptance of this offer by signing below:  My first day 
of employment will be 5/30/95 or before.

Accepted  /s/ D. J. O'Connor  Date 3/25/95
        --------------------       -------
               Don O'Connor