Ref: 14970002
Title: Setting Up a CS/200 for SDLC Pass-Through
Date: 2/27/90

Copyright 3Com Corporation, 1991.  All rights reserved.

CS/200 or CS/210 servers can be set up for SDLC pass-through when using
the XNS protocol.

SDLC uses a bit stuffing technique so that no bit patterns in the data
stream will be confused as the flag pattern.  This produces data frames
whose length may not be a multiple of 8 bits.  Because XNS software can
carry data frames which are not a multiple of eight bits in length, it
supports Bit Sync pass-through.  The IP protocol specification requires a
multiple of eight bits for any data packet, as fragmentation boundaries may
be required in the data path.  Thus, TCP/IP does not support SDLC
pass-through.

Port configuration examples:

LinePRotocol = BITSynchronous
UseDTRin = Ignore
IdleState = LineMark

For Leased Lines:
INTerfaceType = DTE
UseDSRout = (AA,NT)

For Switched Lines:
INTerfaceType = DTE
UseDSRout = (AA,TD)

For Direct connect:
INTerfaceType = DCE
UseDSRout = (OC,NT)

Note:  3Com does not support NRZI.  You can configure the IBM Comms
Controller for NRZ in the NCP line macro, or add an external NRZI/NRZ
converter.

