Specifications

RV-M7 Technical Manual
11
4.3 RS-232/EIA232 Serial I/O Connector
The RS-232 9-pin serial I/O connector is a female 9-pin D-subminiature connector having the following
pins configuration. It is pinned out so that it may be plugged directly into a computer or PC’s 9-pin COM
port.
Front-view of DB-9 connector on modem (female)
Pin
Name
Dir
Function
Level / Specification
1
CD
out
Carrier detect
If enabled, indicates presence of carrier.
Logical 0 (+ voltage on RS-232) means carrier
is present. If disabled, it is asserted (0)
whenever the modem is operational, and not in
the configuration mode. It will be a 1 when the
modem is in the configuration mode. Configured
with the ATR1 setting.
2
RxD
out
Receive data
Data out of the modem.
3
TxD
in
Transmit data
Data into the modem.
4
DTR
in
Data terminal
ready
Normally ignored by the M7 modem. May
control the power-state of the modem in low-
power mode if this feature is enabled.
5
GND
Ground
connection
Signal and power ground
6
DSR
out
Data Set Ready
Normally is set to 0 when modem is powered on
and running. Modem sets to a 1 when in low-
power mode or in command mode.
7
RTS
in
Request to send
Used to stop/start the flow of data coming out of
the modem TxD pin. 0 = OK to send, 1 = don’t
send. Leave disconnected if not used.
8
CTS
out
Clear to send
Used to stop the flow of data going into the RxD
pin from the device connected to the M7. 0 =
OK to send, 1 = don’t send. If the M7 cannot
accept more data, it will negate this signal (set
to a 1).
9
Power
In/out
DC power (not
Ring signal)
User may supply the DC power to the modem
on this pin.