Intel 537EX manual Intel Confidential, Error Correction and Data Compression, +ES=m, see ‘m’

Error Correction and Data Compression

Table 21. V.44/V.42/V.42 bis and MNP Data Modem Command Descriptions (Continued)

Command Default Description

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 <orig_rqst> 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.

+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

m= <orig_rqst>, <orig_fbk>, <ans_fbk> Defaults: m = 3, 0, 2

<orig_rqst> Specifies the initial requested mode of operation when the DCE is the originator. If <orig_rqst>=6, the modem ignores the <orig_fbk> setting.

Range: 1–4, 6

0Reserved.

1Initiate call with buffered mode only.

2Initiate 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.
	<orig_fbk> Specifies the acceptable fallback mode of operation when the DCE is the originator. This
	setting is ignored if <orig_rqst>=6.
+ES=m	Range: 0–2, 4
	see ‘m’	Error control optional (either LAPM or alternative acceptable). If error control is not
	0*
		established, maintain the DTE-DCE data rate and use the V.14 buffered mode with flow
		control during non-error control operation.

1Error 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.

2Error control required (either LAPM or alternative acceptable). If error control is not established, disconnect.

3Reserved.

4Error control required (only alternative protocol acceptable). If error control is not established, disconnect.

<ans_fbk> Specifies the acceptable fallback mode of operation when the DCE is the answerer.

Range: 1, 2, 4–6, 8

0Direct mode.

1Error 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.

3Reserved.

4Error control is required (either LAPM or alternative is acceptable). If error control is not established, disconnect.

5Error control required (only LAPM acceptable). If error control is not established, disconnect.

6Error 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.

NOTE: An asterisk (*) denotes the factory-default setting.

536EX Chipset Developer’s Manual 63

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