SECURITIES AND EXCHANGE COMMISSION
              Washington, D.C. 20549


                   SCHEDULE 13G
     Under the Securities Exchange Act of 1934


              (Amendment No.  10   )*


                      Telco Systems, Inc.                  
                 (Name of Issuer)


                                  
              Common Stock $.01 Par Value        
            (Title of Class Securities)



                878904101                   
                  (CUSIP Number)


    
   Check the following box if a fee is being paid with this statement      .
(A fee is not required only if the filing person: (1) has a previous statement
on file reporting beneficial ownership of more than five percent of the class
of securities described in Item 1; and (2) has filed no amendment subsequent
thereto reporting beneficial ownership of five percent or less of such class.)
(See Rule 13d-7.)

     * The remainder of this cover page shall be filled out for a reporting
person's initial filing on this form with respect to the subject class of
securities, and for any subsequent amendment containing information which
would alter the disclosure provided in a prior cover page.
     
     The information required in the remainder of this cover page shall not be
deemed to be "filed" for the purpose of Section 18 of the Securities Exchange
Act of 1934 ("Act") or otherwise subject to the liabilities of that section of
the Act but shall be subject to all other provisions of the Act (However, see
the Notes).

                        (1)
       SECURITIES AND EXCHANGE COMMISSION
              Washington, D.C.  20549

CUSIP No.        878904101    

     1) Names of Reporting Persons S.S. or I.R.S.
         Identification Nos. of Above Persons:

            Kopp Investment Advisors, Inc.
            I.D. No. 41-1663810

     2) Check the appropriate box if a Member of a Group
         (See Instructions)
         (a)

         (b)  X


     3) SEC Use Only

     4) Citizenship or Place of Organization:

               Minnesota


     Number of shares               5) Sole Voting Power: 
     Beneficially Owned 
     by Each Reporting
     Person With:        6) Shared Voting Power: 


                    7) Sole Dispositive Power:

                                  
                    8) Shared Dispositive Power:
                                                       *  

     9) Aggregate Amount Beneficially Owned by Each Reporting Person:
                                   
                                                       0
     10)  Check Box if the Aggregate Amount in Row (9)
            Excludes Certain Shares (See Instructions)

     11)  Percent of Class Represented by Amount in Row 9:

                                          0%

     12)  Type of Reporting Person (See Instructions):  IA

*Although Kopp Investment Advisors, Inc. exercises investment discretion as
to these shares, it is not the record owner of them.

                        (2)
       SECURITIES AND EXCHANGE COMMISSION
              Washington, D.C.  20549

CUSIP No.         878904101    

     1) Names of Reporting Persons S.S. or I.R.S.
         Identification Nos. of Above Persons:

            Kopp Holding Company
            I.D. No. 41-1875362

     2) Check the appropriate box if a Member of a Group
         (See Instructions)
         (a)

         (b)  X


     3) SEC Use Only

     4) Citizenship or Place of Organization:

               Minnesota


     Number of shares               5) Sole Voting Power: 
     Beneficially Owned
     by Each Reporting
     Person With:        6) Shared Voting Power: 


                    7) Sole Dispositive Power:

                    8) Shared Dispositive Power: 


     9) Aggregate Amount Beneficially Owned by Each Reporting Person:
                                         0

     10)  Check Box if the Aggregate Amount in Row (9)
            Excludes Certain Shares (See Instructions)

     11)  Percent of Class Represented by Amount in Row 9:

                                      0%

     12)  Type of Reporting Person (See Instructions):  HC




                       (2a)
       SECURITIES AND EXCHANGE COMMISSION
              Washington, D.C.  20549

CUSIP No.           878904101    

     1) Names of Reporting Persons S.S. or I.R.S.
        Identification Nos. of Above Persons:

            LeRoy C. Kopp


     2) Check the appropriate box if a Member of a Group
        (See Instructions)
        (a)

        (b)  X


     3) SEC Use Only

     4) Citizenship or Place of Organization:

               United States


     Number of shares               5) Sole Voting Power:  
     Beneficially Owned
     by Each Reporting
     Person With:        6) Shared Voting Power: 


                    7) Sole Dispositive Power:     


                    8) Shared Dispositive Power: 


     9) Aggregate Amount Beneficially Owned by Each Reporting Person:
                                   0

     10)  Check Box if the Aggregate Amount in Row (9)
             Excludes Certain Shares (See Instructions)

     11)  Percent of Class Represented by Amount in Row 9:

                                           0%

     12)  Type of Reporting Person (See Instructions):  IN



                       (2b)
        SECURITIES AND EXCHANGE COMMISSION
              Washington, D.C.  20549


Item 1(a).        Name of Issuer.

                                Telco Systems, Inc.


Item 1(b).        Address of Issuer's Principal Executive
                        Offices.
                                             63 Nahatan Street
                                             Norwood  MA  02062


Item 2(a).        Name of Person Filing.
             
            1. Kopp Investment Advisors, Inc.
            2. Kopp Holding Company
            3. LeRoy C. Kopp
            

           This Statement is filed by Kopp Investment Advisors, Inc.,
           ("KIA") on behalf of all of the above persons pursuant to Rule
           13d-1(f).  Attached is an agreement in writing among the above
           persons that this Statement be so filed on behalf of  each of them. 
          KIA is an investment adviser registered under the Investment
          Advisers Act of 1940.  It is wholly-owned by Kopp Holding
          Company, which is wholly-owned by Mr. Kopp.


            

Item 2(b),2(c),2(d), and 2(e). Address of Principal Business Office;
Citizenship; Title of Class of Securities; CUSIP Number.


           All reporting persons may be contacted at 7701 France Avenue
           South, Suite 500, Edina, MN 55435. Kopp Investment Advisors,
           Inc.  and Kopp Holding Company are Minnesota corporations. 
           Mr. Kopp is a United States citizen.  This report pertains to the
           Common Shares, $.01 par value,  of Telco Systems, Inc.,
           CUSIP #878904101
            
Item 3.    This statement is filed pursuant to Rule 13d-1(b), or 13d-2(b).
                The persons filing include an investment adviser registered
                under Section 203 of the Investment Advisors Act of 1940 and a
                parent holding company in accordance with 13d-1 (b) (ii) (G).
                The other reporting person is filing under SEC release number
                34-39538 II.F.5.

                       (3)
                        
Item 4.       Ownership as of    12/31/98    :

          The information contained in Items 5 - 11 on the
          cover pages is incorporated herein by reference. 


          The filing of this Statement shall not be construed as an
                        admission that the persons filing are beneficial owners
                        of the shares covered by this Statement for any purpose,
                        including purposes of Sections 13, 14 or 16 of the
                        Securities Exchange Act of 1934, as amended.

Item 5.           Ownership of Five Percent or Less of a 
                      Class.
                        If this statement is being filed to 
                        report the fact that as of this date
                        hereof the reporting person has ceased
                        to be the beneficial owner of more than
                        five percent of the class of securities, 
                        check the following [ X ].
                                      

Item 6.           Ownership of More than Five Percent on
                      Behalf of Another Person.

     Of the shares covered by this Statement,                 are held in a
     fiduciary or representative capacity. Accordingly, persons other
     than the reporting persons have the right to receive, or the power to
     direct the receipt of, dividends from, or the proceeds from the sale
     of, such sales.  No person individually has an interest that relates
     to more than five percent of the class.


Item 7.       Identification and Classification of the Subsidiary which
                  Acquired the Security Being Reported on By the Parent
                  Holding Company.
 

                         N/A

Item 8.           Identification and Classification of
                      Members of the Group.
                              
                               
                          N/A


Item 9.           Notice of Dissolution of Group.
                             
                         N/A

                        (4)


Item 10.          Certification.

     By signing below I certify that, to the best of my knowledge and
belief, the securities referred to above were acquired in the ordinary
course of  business and were not acquired for the purpose of and do
not have the effect of changing or influencing the control of the issuer
of such securities and were not acquired in connection with or as a
participant in any transaction having such purposes or effect.



Signature.

     After reasonable inquiry and to the best of my knowledge and belief,
I certify that the information set forth in this statement is true, complete
and correct.



Date:        January 7, 1999      


KOPP INVESTMENT ADVISORS, INC.


By:                                                                   
      Donald B. Cornelius, Secretary/Treasurer























                        (5)


                     AGREEMENT


     The undersigned hereby agrees that the Statement on Schedule 13G to
which this Agreement is attached be filed on behalf of Kopp Investment
Advisors, Inc., a Minnesota corporation; Kopp Holding Company, a
Minnesota Corporation, of which Kopp Investment Advisors, Inc. is
a wholly-owned subsidiary; LeRoy C. Kopp, who holds 100% of
the outstanding capital stock of Kopp Holding Company.



Dated:            January 7, 1999       



KOPP INVESTMENT ADVISORS, INC.


By:                                                             
                         LeRoy C. Kopp


Title:                   President                       



                                                                  
                    LeRoy C. Kopp
 



KOPP HOLDING COMPANY


By:                                                             
              LeRoy C. Kopp, President 












                        (6)