Specifications

Setup & SetUp Command 5-5
changing the baud rate of an RS-232C string. For more information on
changing baud rate, refer to Chapter 3.
Let’s run through an example of changing the baud rate. Assume our sample
module contains the setup data value of ‘31070080’. Byte 2 is ‘07’. By
referring to the SU command chart we can determine that the module is set
for no linefeeds, no parity, and baud rate 300. If we perform the Read Setup
command with this module we would get:
Command: $1RS
Response: *31070080
Let’s say we wish to change the baud rate to 9600 baud. The code for 9600
baud is ‘0010’ (from Table 5.2). This would change byte 2 to ‘02’. To perform
the SU command we must first send a Write Enable command because SU
is write protected:
Command: $1WE
Response: *
Command: $1SU31020080
Response: *
This sequence of messages is done in 300 baud because that was the
original baud rate of the module. The module remains in 300 baud after this
sequence. We can use the Read Setup (RS) command to check the setup
data:
Command: $1RS
Response: *31020080
Notice that although the module is communicating in 300 baud, the setup
data indicates a baud rate of 9600 (byte 2 = ‘02’). To actually change the
baud rate to 9600, send a Remote Reset (RR) command (RR is write
protected):
Command: $1WE
Response: *
Command: $1RR
Response: *
Up to this point all communications have been sent at 300 baud. The module
will not respond to any further communications at 300 baud because it is now
running at 9600 baud. At this point the host computer or terminal must be set
to 9600 baud to continue operation.
If the module does not respond to the new baud rate, most likely the setup
data is incorrect. Try various baud rates from the host until the module