Multi-Tech Systems MT2456SMI22 S41 General Bit Mapped Options Status, S48 V.42 Negotiation Action

Disable negotiation; bypass the detection and negotiation phases; and proceed with LAPM. Enable negotiation. (Default.)

Disable negotiation; bypass the detection and negotiation phases; and proceed at once with the fallback action specified in S36. Can be used to force MNP.

Chapter 4 - V.22bis Commands

S41 - General Bit Mapped Options Status

S41 indicates the status of command options.

Default: 13 (C3h) (00001101b)

Bits 0-1 Compression selection (%Cn).

0= Disabled (%C0).

1= MNP 5 (%C1).

2= V.42 bis (%C2).

3= MNP 5 and V.42 bis (%C3). (Default) Bits 2 Auto retrain (%En).

0= Retrain disabled (%E0).

1= Retrain enabled (%E1). (Default) Bit 3-7 Reserved.

S48 - V.42 Negotiation Action

The V.42 negotiation process determines the capabilities of the remote modem. However, when the capabilities of the remote modem are known and negotiation is unnecessary, this process can be bypassed if so desired. Range: 0, 7, or 128 If an invalid number is entered, it is accepted into the S-Register, but S48 will act as if 128 has been entered.

Default: 7 S48=0 S48=7 S48=128

S82 - Break Handling Options

Break Signals provide a way for the user to get the attention of the remote modem. The break type depends on the speed application. LAPM specifies three methods of break signal handling; in sequence, expedited, and destructive, If an in number is entered, it is accepted into the S register, but S82 will act as if the default value has been entered. Range: 3,7, or 128

Default: 128

S82 = 3 Expedited: Modem sends a break immediately; data integrity is maintained ahead of and after the break.

S82 = 7 Destructive: Modem sends a break immediately; data being processed by each modem at the time of the break is destroyed.

S82 =128 In sequence: Modem sends a break in sequence with any transmitted data; data integrity is maintained both ahead of and after the break (default)

S86 - Call Failure Reason Code

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. Code definitions are: Range: 0-26

Default: 21

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.

Multi-Tech Systems, Inc. MT2456SMI-22 SocketModem Developer’s Guide 43