© Microhard Systems Inc.
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6.0 Configuration
6.3 Serial Interface Commands
A number of register settings are specifically related to the serial data interface.
Some, which have been discussed previously, include:
S102 Serial Baud Rate
determines the rate of communications be-
tween the modem and the local device
S110 Data Format
defines the data, stop, and parity bit count
S142 Serial Channel Mode
selects the actual serial interface to be used
S217 Protocol Type
defines the nature of the incoming data and
what, if any, special action should be taken
by the modem upon the data
Also, there are AT commands which effect the configuration of the module, specifical-
ly with respect to the handling of data at the RS-232 interface:
&C Data Carrier Detect (DCD)
&D Data Terminal Ready (DTR)
&K Handshaking
&S Data Set Ready (DSR)
The above four items are discussed further in this section.
Values
&Cn
Data Carrier Detect (DCD)
0 DCD always on
1 DCD on when
modems
synchronized*
2 DCD used for output data
framing and Modbus mode
Controls the module’s DCD output signal to the attached device. Determines when
the DCD line is active.
*DCD always on when
module configured as a
Master