Z02215
Single Chip Modem with Integrated Controller, Data Pump, and AFE
17
Table 3. AT Command Set (Continued)
Function and Description
Command
B0
This option specifies the ITU-T modulation standards for all
telephone line data rates unless S-register S37 is 2. These
rates include V.22 for the 1200 bps telephone line data rate,
and V.21 for the 300-bps telephone line data rate.
When the value of S-register S37 is 1and the originating
modem is transmitting at 75 bps and receiving at 1200 bps,
V.23 is utilized. The answering modem transmits data at
1200 bps and receives data at 75 bps. When the value of S-
register S37 is 2 and the originating modem is transmitting
at 150 bps and receiving at 1200 bps, Bell 202 is utilized.
The answering modem transmits data at 1200 bps and
receives data at 150 bps.
B1
This option specifies the Bell modulation standards for 1200
bps and 300 bps telephone line data rates, unless S-
register S37 is 1. Bell 212A at 1200 bps is utilized instead of
V.22. Bell 212A, V.22 is the default value for North America.
Bell 103 is utilized when a 300 bps telephone line data rate
is required.
If neither the 1200 bps nor 300 bps telephone line data rate
are required, then a setting of B1 is ignored and the modem
operates as if B0 was set.
B2
When the value of S-register S37 is 1 and when the
originating modem is transmitting at 1200 bps and receiving
at 75 bps V.23 B1 is selected. The answering modem
transmits data at 75 bps and receives data at 1200 bps.
When the value of S register S37 is 2 and when the
originating modem is transmitting at 1200 bps and receiving
at 150 bps, Bell 202 is utilized. The answering modem
transmits data at 150 bps and receives data at 1200 bps.
When S-register S37 is set to any value other than 1 or 2,
then a setting of B2 operates as if B0 is set.
B3
This option is the same as B0.
PS001907-0904
AT Command Set
ZILOG [ ZILOG, INC. ]
