Intel 537EX manual Intel Confidential, Data Mode AT COMMANDS, Supported Modulation Types

Data Mode AT COMMANDS

Table 16. Supported Modulation Types

<carrier >	Description
Bell 103	300 bps
Bell 212A	1200 bps
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, 28,800, 31,200, and 33,600 bps
	56K V.90 asymmetrical connections (transmit): 4800, 7200, 9600, 12,000, 14,400, 16,800,
	19,200, 21,600, 24,000, 26,400, and 28,800, 31,200, and 33,600 bps
V90	56K V.90 asymmetrical connections (receive): 28,000, 29,333, 30,666, 32,000, 33,333, 34,666,
	36,000, 37,333, 38,666, 40,000, 41,333, 42,666, 44,000, 45,333, 46,666, 48,000, 49,333,
	50,666, 52,000 53,333, 54,666, and 56,000 bps
	56K V.92 asymmetrical connections (transmit): 24,000, 25,333, 26,666, 28,000, 29,333, 30,666,
	32,000, 33,333, 34,666, 36,000, 37,333, 38,666, 40,000, 41,333, 42,666, 44,000, 45,333, 46,666
V92	and 48,000 bps
	56K V.92 asymmetrical connections (receive): 28,000, 29,333, 30,666, 32,000, 33,333, 34,666,
	36,000, 37,333, 38,666, 40,000, 41,333, 42,666, 44,000, 45,333, 46,666, 48,000, 49,333,
	50,666, 52,000, 53,333, 54,666, and 56,000 bps

If the +MS=m parameters contain conflicting information like “+MS=V34,1,14400,0” with a DTE data rate of 2400 bps, then the modem’s connection attempts always fail, and the modem reports a “NO CARRIER” message. This happens because when the modem receives the +MS=m command, the modem does not check for conflicts of valid parameter information.

Table 17 shows the resulting connection data rate when using non-default values. Because of impairments on the telephone line, the actual connection speeds may be lower than the speeds defined in this table.

For V.92, V.90, and V.34 modulation, the modem can receive data at a different data rate than the transmit data rate. All other modulation types besides V.23 and V.34 use the same data rate for the transmitter and receiver. Use ATW3 to see the modem’s actual receive and transmit data rates (the modem must be configured for ATV1 text response codes). Table 17 shows examples of the resulting connection rate when non-default values are used.

536EX Chipset Developer’s Manual 35

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