Motorola g20 Developer's Manual page 164

AT Commands Reference
AT+MTDTR=?
OK
4.7.1.6 +MTCTS, CTS Line Test Command
This command sets the CTS pin of the RS232 to active high, waits one second and then returns the CTS to active low.
Set Command
Command
AT+MTCTS=
Read Command
Command
AT+MTCTS
Test Command
Command
AT+MTCTS=?
Example
AT+MTCTS
OK
4.7.1.7 &K, RTS/CTS Flow Control
This command configures the flow control. The RTS (Request To Send) is an input line. The RTS signal is received from the
terminal and a low condition indicates that the g20 can send more data. The CTS (Clear To Send) is an output line. The CTS
signal is sent to the terminal and a low state indicates that more data can be sent to the g20.
The RTS and CTS together make up what is called RTS/CTS or "hardware" flow control. Both lines are used when "hardware
flow control" is enabled in both the terminal and the g20 devices. When the terminal is ready and able to receive data, it puts
the CTS line in an active (low) condition to indicate this to the g20. If the terminal is not able to receive data (typically because
its receive buffer is almost full), it puts the CTS line in an inactive (high) condition as a signal to the g20 to stop sending data.
When the terminal is ready to receive more data (for example, after data has been removed from its receive buffer), it places this
line back in the active condition. The RTS wire complements the CTS line. The g20 puts the RTS line in an active condition to
tell the terminal that it is ready to receive the data. Likewise, if the g20 is unable to receive data, it places the RTS line in an
inactive condition.
150
Response/Action
+CME ERROR: <err>
Response/Action
OK
Response/Action
+CME ERROR: <err>
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