Chapter 5 – AT Commands, S-Registers, and Result Codes
Multi-Tech Systems, Inc. SocketModem MT5600SMI Developer’s Guide 81
Register Unit Range Default Description
S86 0–26 21 Call Failure Indication. When the modem issues a NO CARRIER
result code, a value is written to S86 Register to help determine the
reason for the failed connection. S86 records the first event that
contributes to a NO CARRIER message. The code definitions are:
S86=0 Normal hangup, no error occurred.
S86=1 Reserved.
S86=2 Reserved.
S86=3 Call Waiting caused disconnect.
S86=4 Physical carrier loss.
S86=5 No error correction at the other end.
S86=6 No response to feature negotiation.
S86=7 This modem is async only; the other modem is sync only.
S86=8 No framing technique in common.
S86=9 No protocol in common.
S86=10 Bad response to feature negotiation.
S86=11 No sync information from the remote modem.
S86=12 Normal hangup initiated by the remote modem.
S86=13 Retransmission limit reached.
S86=14 Protocol violation occurred.
S86=15 Lost DTR.
S86=16 Received GSTN cleardown.
S86=17 Inactivity timeout.
S86=18 Speed not supported.
S86=19 Long space disconnect.
S86=20 Key abort disconnect.
S86=21 Clears previous disconnect reason.
S86=22 No connection established.
S86=23 Disconnect after three retrains.
S86=24 Call Waiting tone detected.
S86=25 Extension pickup detected.
S86=26 Remote hangup detected.
S91 dBm 0–15 10 PSTN Transmit Attenuation Level. In non-PCM modes (V.90 or
K56flex are PCM modes), S91 sets the transmit attenuation level from
0 to 15 dBm for the PSTN mode, resulting in a transmit level from 0 to
-15 dBm. In some countries, the transmit level may not be changed
and there are checks to prevent transmit attenuation level change.
The default is country dependent.
S95 0 Extended Result Codes Control. A bit set to a 1 in this parameter,
in conjunction with the W command, will enable the corresponding
extended result code. *
The +MR, +ER, and +DR settings also control S95 bits 2, 3, and 5,
respectively. The more recent settings of +MR, +ER, and +DR, or
host writing of S95 bits 2, 3, and 5, along with the W command
setting, determine the corresponding actual result code reporting (see
+MR, +ER, DR, and W commands).
Bit 0 CONNECT result code indicates DCE speed instead of DTE speed.
Bit 1 Append/ARQ to CONNECT XXXX result code in error-correction
mode (XXXX = rate).
Bit 2 Enable +MCR: XXXX result code (XXXX = modulation) and
+MRR: XXXX result code (XXXX = rate). (Also, see +MR.)
Bit 3 Enable +ER: XXXX result code (XXXX = protocol identifier).
Bit 4 Reserved.
Bit 5 Enable +DR: XXXX result code (XXXX = compression type).
Bits 6-7 Reserved.