Company Confidential
10
Raveon Technologies Corp.
4. Electrical Inputs and Outputs
4.1. LEDs
Status LED (TX)
This LED blinks indicates the status of the device as follows:
Color
Power LED (PWR)
This LED does a short blink, once every two seconds, indicating to the
user that the power to the modem is ON and the modem is working. When the modem is in
the command mode, this LED will blink on and off, once per second.
4.2. I/O Pinout
The I/O connector is a 20-pin header, 2mm pin spacing.
Pin #
Function
I/O
Function
1
GND
-
Ground
2
Vcc
I
DC Input
3
CD
O
Carrier Detect Out. Low for carrier. Logic high for no carrier.
RF
or
DATA
carrier detect set with ATR1 command. Default: RF.
4
TX On
O
Pin is High when module is transmitting. Low when off, receiving, or
sleeping.
5
Data In (TXD)
I
Transmit data input.
6
Data Out (RXD)
O
Receive data output.
7
Enable
I
Low (<.7V) to shut down the module. High (>2.5V) to enable it.
8
Sleep
i
CPU Sleep input
9
CTS
O
Clear to send output. Indicates state of internal input buffer.
ATJF command sets the threshold where CTS is negated.
10
RTS
I
RTS input for serial flow control.
11
RSSI
0
Receiver signal strength indicator
12
3.3V out
O
3.3V out of the M8 module. 50mA max current draw.
13
IOA
AUDIO IN
I/O
General purpose digital I/O. 3V digital logic from CPU on M8. If the
Audio option is used, this pin is used to input transmit audio.
14
IOB
I/O
General purpose I/O. 3V digital logic from CPU on M8. By default
functions as DSR. 0= ready&running. 1=sleeping. If enable=0, this
line will =0.
15
IOC
I
Reserved.
16
STAT1
O
Output to drive external dual-color LED. Connect led between
STAT1 and STAT2.
17
RX Audio
O
Receive and transmit audio output for factory test. Do not connect to
anything. If the AUDIO option is used, this pin is the receive audio
output.
18
STAT2
O
Output to drive external dual-color LED. Do not connect the LED to
ground or DC voltage.
19
GND
-
System Ground to M8
20
Vbu
I
Backup battery input to CPU to retain memory. Not required to be
connected to anything.
