COMSPHERE 3800Plus Modems
8-34 October 1998 3980-A2-GB30-40
Table 8-6
(2 of 8)
V.42/MNP/Buffer Configuration Options
Sync Comp Mode: DirectMode
Nxt DirectMode HDLC/SDLC
This configuration option only appears if Async/Sync Mode is configured for Sync.
Synchronous Compression Mode. Enables and disables synchronous data compression.
DirectMode – Disables the Synchronous Data Compression mode.
HDLC/SDLC – Enables the Synchronous Data Compression mode
The AT command for Sync Comp Mode is #SC
n
.
SDC Negotiation: LAPM_Buffer
Nxt LAPM_Buffer LAPM_Discon
This configuration option only appears when the Async/Sync Mode configuration option is set to Sync, and
Sync Comp Mode configuration option is
not
set to DirectMode.
Synchronous Data Compression Negotiation. Determines the type of negotiation used when the modem attempts to
connect using SDC. See Table I-1 in Appendix I,

Synchronous Data Compression

.
Link Access Procedure for Modems or Buffer – The modem attempts to establish an SDC connection. If the remote
modem has SDC capability, then the connection is established with SDC active. If the remote synchronous modem does
not have SDC capability, then the local connection is made in Buffer mode.
Link Access Procedure for Modems or Disconnect – The modem attempts to establish an SDC connection. If the
remote modem has SDC capability, then the connection is established with SDC active. If the remote modem does not
have SDC capability, then no connection occurs and the modem generates a disconnect.
The AT command for SDC Negotiation is S28=
n
.
SDC Idle Fill: Flag_Fill
Nxt Flag_Fill Mark_Fill
This configuration option only appears when the Async/Sync Mode configuration option is set to Sync, and
Sync Comp Mode configuration option is
not
set to DirectMode.
Synchronous Data Compression Idle Fill. Determines whether the modem uses an HDLC flag or mark to fill the time
between DTE frame transfers.
Flag_Fill – Causes the modem to fill the time between DTE frame transfers with HDLC flags.
Mark_Fill – Causes the modem to fill the time between DTE frame transfers with marks.
The AT command for SDC Idle Fill is S29=
n
.
SDC BitEncoding: NRZ
Nxt NRZ NRZI
This configuration option only appears when the Async/Sync Mode configuration option is set to Sync, and
Sync Comp Mode configuration option is
not
set to DirectMode.
Synchronous Data Compression Bit Encoding. Determines the type of bit encoding scheme (NRZ or NRZI) the modem
uses when transmitting synchronous DTE data.
NRZ – Causes the modem to use the standard Non Return to Zero bit encoding scheme.
NRZI – Causes the modem to use the Non Return to Zero Inverted bit encoding scheme.
The AT command for SDC Bit Encoding is S31=
n
.