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536EX Chipset Developer’s Manual 35
Intel Confidential
Data Mode AT COMMANDS
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.
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
V90
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
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
V92
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
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