XBee
‐
PRO®
XSC
RS
‐
232/RS
‐
485/USB
RF
Modem
‐
Product
Manual
©
2013
Digi
International,
Inc.
12
Sample Wireless Connection: DTE <--> DCE
DCE <--> DCE
Figure
2
‐
04. Typical
wireless
link
between
DTE
and
DCE
devices
2.2. RS-485 (2-wire) Operation
Note that with the RS-485 variant of the XSC RF Modem, the RF Modem is defaulted with the CS
command (AT parameter) to 3. This parameter controls the TX enable signal and allows the
modem to output any data in the DO buffer to the host device for the RS-485 interface. In the
event that the parameter is accidentally changed, which would result in RS-485 communication
being halted, a USB mini cable should be plugged into the modem to reconfigure it. The
reconfiguration can be done by using Digi’s X-CTU.
With the USB plugged in, open X-CTU and select the Com port of the USB. Select the Terminal tab
and type '+++'. The system will respond with 'OK'. Type 'ATCS3' then <Enter>, and the system
will respond with 'OK'. Type 'ATWR' then <Enter>, and the system will respond with 'OK'. Type
'ATCN' then <Enter> to exit command mode, and the system will respond with 'OK'. Unplug the
USB and return to the existing RS-485 interface. The XSC RF Modem is now ready to
communicate in RS-485 mode.
NOTE:
Failure
to
enter
AT
Command
Mode
is
most
commonly
due
to
baud
rate
mismatch.
Ensure
the
‘Baud’
setting
on
the
“PC
Settings”
tab
matches
the
BD
(Interface
Data
Rate)
setting
of
the
RF
modem
(by
default,
BD
parameter
=
3,
which
is
associated
to
9600
baud).