Multitech MultiModemDSVD User Manual page 55

4 AT Commands, S-Registers, and Result Codes
Register Unit Range
S86 decimal 0, 4, 5, 9, n/a
12, 13, 14
Default Description
When the modem issues a NO CARRIER
result code, a value is written to this
register to help determine the reason for
the failed connection. S86 records the first
event that contributes to a NO CARRIER
message. Use the S86? command to read
the value.
0 Normal disconnect; no error occurred.
4 Loss of carrier.
5 V.42 negotiation failed to detect an
error-correction modem at the other
end.
9 The modems could not find a common
protocol.
12 Normal disconnect initiated by the
remote modem.
13 Remote modem does not respond after
10 retransmissions of the same message.
14 Protocol violation.
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