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DDN MGT Bulletin 100              DISA DDN Defense Communications System   
11 August 1992                    Published by: DDN Network Info Center
                                      (NIC@NIC.DDN.MIL)  (800) 365-3642


                        DEFENSE  DATA  NETWORK
                         MANAGEMENT  BULLETIN

  The DDN MANAGEMENT BULLETIN is distributed online by the DDN Network
  Information Center under DISA contract as a means of communicating
  official policy, procedures and other information of concern to
  management personnel at DDN facilities.  Back issues may be read
  through the TACNEWS server ("@n" command at the TAC) or may be
  obtained by FTP (or Kermit) from the NIC.DDN.MIL host [192.112.36.5]
  using login="anonymous" and password="guest".  The pathname
  for bulletins is ddn-news/ddn-mgt-bulletin-nn.txt (where "nn" is the
  bulletin number).
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                    Correction to CODEX Modem Procedures

 1.  Several users have pointed out that DDN Management Bulletin 95 was not
     solving their problems when logging onto TAC dial-in circuits using CODEX
     modems.  Upon reviewing the proposed workaround, DISA determined that a
     portion of the workaround had been omitted from the management bulletin.
     This bulletin corrects that oversight.  

 2.  Bulletin 95 stated that script or login files could be modified to pause
     approximately 6 seconds, and then transmit the control-q character.  In
     addition to the pause, a carriage return must be added to the script
     after the control-q.  If this fails to cause the TAC banner to be
     transmitted to the terminal, a second carriage return should be added to
     the script.  It has been our experience that this process allows users of
     modems that do not have the Microcomm Network Protocol (MNP) to operate
     with the CODEX dial-in modems.  For users that do not use script or login
     files, the workaround would be as follows.  

        a.  Dial the TAC as usual.  

        b.  After receiving the connect message on the modem, transmit
            control Q.

        c.  If the TAC banner does not print on your terminal, wait a few
            seconds and then transmit a carriage return.

        d.  If this fails to cause the TAC banner to be displayed, repeat
            the process from step b.

     If you do not receive the TAC banner after two attempts, contact the
     NIC (1-800-365-DNIC) for assistance.

 2.  The difference between the CODEX modems and the AT&T modems (beside speed)
     is that the CODEX modems implement an error-correcting option called
     the Microcomm Network Protocol (MNP).  If you have a modem that uses MNP
     level 4 or 5, you will not experience the 6-second pause.  The CODEX
     modems will still ignore the control Q, but the sequence <control Q,
     carriage return> should cause the TAC to issue the banner.  If this
     fails, lower your speed setting to 1200 BPS and try again.  Remember
     that the AT&T modem's maximum speed is 1200 BPS.  If this also fails,
     contact the NIC for assistance.

 3.  If the NIC is unable to solve the problem, it should be escalated to the
     CONUS MILNET Monitoring Center for action since these modems are currently
     used only in CONUS.  Please contact the Monitoring Center at
     1-800-451-7413.
     
 4.  This bulleting was prepared by Maj Tatchio, MILNET Mgr, HQ DISA, 
     DSN 222-7580, commercial (703) 692-7580.