3Com Courier Reference page 165

Command Function
n = 1 -16
Ampersand (&) Command Set
Fixed rate. The modem connects only if the
remote device is operating at the same rate. You
can use this feature to filter out calls at other than
a specific rate for security or other reasons.
The connection rate must always be lower than or
equal to the serial port rate.
n=1
n=2
n=3
n=4
n=5
n=6
n=7
n=8
n=9
n=10
n=11
n=12
n=13
n=14
n=15
n=16
n=17
n=18
n=19
n=20
n=21
n=22
n=23
n=24
n=25
n=26
n=27
n=28
B-9
300 bps
1200 bps
2400 bps
4800 bps
7200 bps
9600 bps
12000 bps
14400 bps
16800 bps
19200 bps
21600 bps
24000 bps
26400 bps
28800 bps
31200 bps
33600 bps
28000 bps
29333 bps
30666 bps
32000 bps
33333 bps
34666 bps
36000 bps
37333 bps
38666 bps
40000 bps
41333 bps
42666 bps