Intel MD566X manual +MS=m See m, V34BS

56K V.92 Data, Fax, and Voice Chipset

Table 3-4. Data Mode Command Descriptions (Continued)

Modulation Selection: This command sets the type of modulation used and the send and receive speeds. Settings for Bn, +MS=m, Nn and S37 determine the al- lowable modem connections. Nn performs the same function as the +MS=m <auto- mode> parameter. S37 performs the same function as the +MS=m <max rate> pa- rameter.

Modems using MD566X chipsets can be configured by the +MS=m command to support only asymmetrical or symmetrical connections. The transmit and receive speeds are the same in symmetrical connections and different in asymmetrical con- nections. The type of connection is set by the <carrier> parameter. The chipsets default to the ITU-T V.90 or V.92 mode depending on firmware version. If the con- nection is non-V.90/V.92 the chipsets fall back to V.34 mode. Note that the transmit- ter speed and receiver speeds typically are different for most V.34 connections over the PSTN.

The +MS command sets the modulation speeds in the V.34 chipsets; however, B0 also must be sent to set the modulation to V.22. Sending B1 sets the modulation to Bell 212. These commands can be typed before or after the +MS command. For ex- ample, to set the modulation to ITU-T V.22:

+MS = V22, 1, 1200, 1200; B0

To check the settings for the +MS command, type AT+MS?

m = <carrier>, <automode>, <min rate>, <max rate>

+MS=m	see “m”	Defaults: m = V90, 1, 0, 0
		<carrier > This eight-digit string parameter specifies the type of modulation used.
		Approved codes are shown in the following table. The modem can switch automati-
		cally between some types.
		<carrier>	Description
		V21	V.21	300 bps
		V22	V.22	1200 bps
		V22B	V.22 bis 1200 and 2400 bps
		V23C	V.23, with constant carrier; 1200 bps forward and 75 bps reverse
		V32	V.32	4800 and 9600 bps
		V32B	V.32 bis 7200, 9600, 12,000, and 14,400 bps
		V34	V.34	asymmetrical connections: 2400, 4800, 7200, 9600, 12,000,
			14,400, 16,800, 19,200, 21,600, 24,000, 26,400, and 28,800 bps
		V34S	V.34	symmetrical-only connections: 2400, 4800, 7200, 9600,
			12,000, 14,400, 16,800, 19,200, 21,600, 24,000, 26,400, 28,800
			bps
		V34B	V.34 extended asymmetrical connections: 2400, 4800, 7200, 9600,
			12,000, 14,400, 16,800, 19,200, 21,600, 24,000, 26,400, 28,800,
			31,200, and 33,600 bps
		V34BS	V.34 extended symmetrical connections: 2400, 4800, 7200, 9600,
			12,000, 14,400, 16,800, 19,200, 21,600, 24,000, 26,400, 28,800,
			31,200, and 33,600 bps

56 Intel Confidential Programmer’s Guide