LANE, ALTMAN OWENS LLP                101 Federal Street            Telephone
                                      Boston, Massachusetts         617-345-9800
 Counsellors at Law                   02110
                                                                    Telefax
                                                                    617-345-0400




                                                              September 16, 1999


Datametrics Corporation
25B Hanover Road, Suite 3305
Florham Park, New Jersey 07932

         Re:      Registration  Statement  on Form SB-2  Relating to  12,753,380
                  Shares  of  Common  Stock,  of  Datametrics  Corporation  (the
                  "Company")

Gentlemen:

         You have asked us to render an opinion in connection with the filing by
the Company of a Registration Statement on Form SB-2 ("Registration  Statement")
with the Securities and Exchange  Commission,  pursuant to the Securities Act of
1933,  as amended (the "Act"),  registering  an aggregate  12,753,380  shares of
Common Stock of the  Company,  $0.01 par value,  consisting  of shares of Common
Stock  currently  issued  and  outstanding,  shares of Common  Stock  underlying
Warrants  ("Warrant  Shares")  and  shares of  Common  Stock  issuable  upon the
conversion of Convertible  Notes  ("Conversion  Shares," and  collectively,  the
"Shares")  which were issued by the Company to certain  selling  shareholders in
private transactions ("Selling Shareholders").

         In our capacity as your counsel, we have examined and are familiar with
originals or copies,  certified or otherwise identified to our satisfaction,  of
the  Company's  Certificate  of  Incorporation  and  amendments  thereto and the
Company's  Amended and Restated  By-Laws,  as each is  currently in effect,  the
Registration Statement, and the proposed registration and issuance of the Shares
and such other corporate documents and records and other certificates, including
a  Certificate  of the  Secretary  of State  of the  State  of  Delaware,  dated
September 16, 1999, as to the Legal  Existence and Good Standing of the Company,
and we have made  such  investigations  of law as we have  deemed  necessary  or
appropriate in order to render the opinions hereinafter set forth.

         In our examination,  we have assumed the genuineness of all signatures,
the legal capacity of all natural  persons,  the  authenticity  of all documents
submitted  to us as  originals,  the  conformity  to original  documents  of all
documents submitted to us as certified or photostatic







          LANE, ALTMAN OWENS LLP
           Counsellors at Law                                 September 16, 1999
                                                              Page 2



copies and the authenticity of the originals of such latter documents. As to any
facts  material to the opinions  expressed  herein which were not  independently
established or verified,  we have relied upon statements and  representations of
officers and other representatives of the Company and others.

         We further inform you that we do not purport to practice under the laws
of any jurisdiction  other than the Commonwealth of Massachusetts and the United
States of  America.  We have,  therefore,  not made an  independent  review  and
express no opinion  with regard to the laws of any  jurisdiction  other than the
laws of the Commonwealth of  Massachusetts,  the General  Corporation Law of the
State of Delaware, and the United States of America.

         Based upon and subject to the foregoing, we are of the opinion that:

         1.       The Company has been duly organized,  is validly existing, and
                  in good standing under the laws of the State of Delaware.

         2.       The  currently  issued and  outstanding  Shares have been duly
                  authorized,   and  are   legally   issued,   fully   paid  and
                  non-assessable,  and,  upon the  exercise of the  Warrants and
                  conversion   of  the   Convertible   Notes   by  the   Selling
                  Shareholders,  the Warrant Shares and Conversion Shares,  when
                  issued,  delivered and paid for, will be legally issued, fully
                  paid and non-assessable.

         We hereby  consent to the use of this  opinion  as  Exhibit  5.1 to the
Registration Statement,  and to the use of our name as counsel to the Company in
connection with the Registration  Statement and in the Prospectus forming a part
thereof.  In giving this consent,  we do not thereby concede that we come within
the  categories  of the  persons  whose  consent is  required  by the Act or the
General Rules and Regulations promulgated thereunder.




                                                     Very truly yours,

                                                     /s/ Lane Altman & Owens LLP
                                                     ---------------------------
                                                     LANE, ALTMAN & OWENS, LLP