Multi-Tech Systems MT2456SMI22 - Manual (Page 31)

Chapter 4 - V.22bis Commands
Multi-Tech Systems, Inc. MT2456SMI-22 SocketModem Developer’s Guide 31
V.22bis Synchronous Access Mode
Commands
Three commands support Synchronous Access Mode:
+ES enables and disables Synchronous Access Mode in the client or central site modem. Enabling Synchronous
Access Mode enables the use of the 8-bit command characters of the Draft ITU-T Recommendation V.80 (See
the table under the +IBC command - Data Communication over the Telephone Network. In-Band DCE Control
Command).
+ESA configures the operation of the Synchronous Access Submode
+ITF selects Transmit Flow Control Thresholds
+ESA Configure Synchronous Access Submode
The operation of the Synchronous Access sub-Mode is configured by the +ESA parameter ..
This extended-format compound parameter is used to control the manner of operation of the Synchronous Access
Mode in the modem. It accepts six numeric subparameters:
Syntax
+ESA=[[,[,[,[,[,[,[,]]]]]]]]
Defined Values
Specifies the bit sequence transmitted by the modem when a transmit data buffer under run
condition occurs, while operating in Transparent sub-Mode. The options are:
0 In Transparent sub-Mode, modem transmits 8-bit SYN sequence on idle. Modem receiver
does not hunt for synchronization sequence (default and fixed).
Specifies the bit sequence transmitted by the modem when a transmit data buffer under run
condition occurs immediately after a flag, while operating in Framed sub-Mode. The options are:
0 In Framed sub-Mode, modem transmits HDLC flags on idle (default and fixed).
Specifies the actions undertaken by the modem when a transmit data buffer under run or overrun
condition occurs immediately after a non-flag octet, while operating in Framed sub-Mode.
0 In Framed sub-Mode, modem transmits abort on under run in middle of frame (default).
1 In Framed sub-Mode, DCE transmits a flag on under run in middle of frame, and notifies
DTE of under run or over run.
This subparameter should not be commanded.
Specifies the CRC polynomial used while operating in Framed sub-Mode. The options are:
0 CRC generation and checking disabled (default).
1 In Framed sub-Mode, the 16-bit CRC is generated by the modem in the transmit direction,
and checked by the modem in the receive direction.
Specifies if Non Return to Zero Inverted (NRZI) encoding is to be used by the modem for transmit
and receive data. The options are:
0 NZRI encoding and decoding disabled (default and fixed).
, Specifies the octet value(s) to be used while performing character-oriented framing. is to be
commanded to 255 (FFh); is not to be commanded.
Reporting Selected Options
The modem reports the selected options in response to the following command:
+ESA?
The response is:
+ESA:
,,,,,,,
Example:
+ESA?
+ESA: 0,0,0, ,0,0,255, For the defaults.
Reporting Supported Options
The modem reports the supported options in response to the following command:
+ESA=?
The response is:
+ESA: (list of supported values), (list of supported values),(list of supported
values), (list of supported values),(list of supported values), (list of supported
values),(list of supported values), (list of supported values)
Example:
+ESA=?
+ESA: (0),(0),(0-1), ,(0-1),(0),(255),