Intel 537EX - Manual (Page 63)

536EX Chipset Developer’s Manual 63
Intel Confidential
Error Correction and Data Compression
+ES=m see ‘m’
Error Control Selection: The +ES=m command controls the operation of the V.42 error detection and
correction protocol in the DCE. Once a connection has been established between the DCE and DTE, the
subparameter can put the interface into synchronous access mode. In the default settings,
synchronous access mode is disabled. To change modes, send another +ES command.
m = , ,
Defaults: m = 3, 0, 2
Specifies the initial requested mode of operation when the DCE is the originator. If
=6, the modem ignores the setting.
Range: 1–4, 6
0 Reserved.
1 Initiate call with buffered mode only.
2 Initiate V.42 without detection phase. If V.80 mode is in use, this is a request to disable V.42
detection phase.
3* Initiate V.42 with detection phase.
4 Initiate alternate protocol.
6 Initiate synchronous access mode when connection is completed and when in data state.
Specifies the acceptable fallback mode of operation when the DCE is the originator. This
setting is ignored if =6.
Range: 0–2, 4
0* Error control optional (either LAPM or alternative acceptable). If error control is not
established, maintain the DTE-DCE data rate and use the V.14 buffered mode with flow
control during non-error control operation.
1 Error control optional (either LAPM or alternative acceptable). If error control is not
established, change the DTE-DCE data rate to match the line rate and use direct mode.
2 Error control required (either LAPM or alternative acceptable). If error control is not
established, disconnect.
3 Reserved.
4 Error control required (only alternative protocol acceptable). If error control is not established,
disconnect.
Specifies the acceptable fallback mode of operation when the DCE is the answerer.
Range: 1, 2, 4–6, 8
0 Direct mode.
1 Error control disabled, use buffered mode.
2* Error control optional (either LAPM or alternative acceptable). If error control is not
established, maintain the DTE-DCE data rate and use local buffering and flow control during
non-error control operation.
3 Reserved.
4 Error control is required (either LAPM or alternative is acceptable). If error control is not
established, disconnect.
5 Error control required (only LAPM acceptable). If error control is not established, disconnect.
6 Error control required (only the alternative protocol is acceptable). If error control is not
established, disconnect.
8 Initiate synchronous access mode when the connection is complete and data state is entered.
Table 21. V.44/V.42/V.42 bis and MNP Data Modem Command Descriptions (Continued)
Command Default Description
NOTE: An asterisk (*) denotes the factory-default setting.
+ES=1,0,1 Buffered mode
+ES=4,4,6 MNP reliable mode
+ES=3,0,2* V.42 autoreliable mode
+ES=3,2,4 V.42 reliable mode
+ES=2,3,5 LAPM reliable mode
+ES=6, ,8 Synchronous access mode