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USWD500 User’s Manual Version 3.0
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Adjust the baud rate using the
AT&L
n
command (where
n
is the desired baud
rate). For example:
AT&L9600
Changes the baud rate to 9600 bps
ok
Note
: After changing the baud rate setting, you must also change the baud rate
setting in your communications program on your host device to the same
value. Otherwise, the host device will no longer communicate with the
USWD500 Modem.
Hardware Flow Control Setup
RTS/CTS flow control is part of a family of flow-control methods collectively
referred to as “hardware flow control.” Hardware flow control methods use RS-232
control lines to start and stop the flow of serial data. With RTS/CTS, the host uses
RTS to start and stop the flow of data from the USWD500 Modem. The USWD500
Modem uses CTS to start and stop the flow of data from the host. This process is
described in the following illustration:
When RTS is inactive, the USWD500 Modem cannot send data to the host. For
the same reason, when the USWD500 Modem is busy transmitting data to the
CDPD network, it asserts CTS to stop the flow of data. An example of the
command for controlling hardware flow is provided below:
AT\Q2
Enable hardware flow control
ok
serial data to modem
serial data to host
RTS/CTS Hardware Flow Control
USWD500 Modem
RTS
Host PC
Controls the flow
of serial data
from the modem
CTS
Controls the flow
of serial data
from the host