Sierra Wireless MP 875 - Manual (Page 36)

MP875 Modem User Guide
36 2130808
Serial connector (DB9) pinouts
The MP modem is configured as DCE (Data Communications
Equipment) and uses the standard RS232 pin designations:
Figure 3-8: Pinouts for an RS232 male DB9 serial cable (left) that connects to
the MP modem’s female DB9 serial connector (right). Note that the two figures’
pinouts are mirror images of each other, since they plug together.
The serial connector uses these voltage specifications:
Figure 3-9: Voltage specifications for the MP modem’s serial connector.
Install the USB, Ethernet or serial cable
Note: Ensure that the MP
modem and your computer are
powered off while installing
cables. To install the USB, Ethernet, or serial cable, thread the cable
through the vehicle and attach it to the USB, Ethernet, or serial
connector on the MP modem.
Note: Do not connect the cables to the computer until you have
installed the software. If you have an MP 595W and are planning on
using a WAP connection, see “Plan your MP modem installation” on
page 20 for more information.
3. Received Data (RxD)*
2. Transmitted Data (TxD)*
4. Data Terminal Ready (DTR)
5. Signal Ground (GND)
6. Data Set Ready (DSR)
7. Clear To Send (CTS)
8. Request To Send (RTS)
9. Ring Indicator (RI)
DB9 MALE
* RxD and TxD are named with respect to the MP modem
(that is, RxD is the Receive Data input to the MP modem,
and TxD is the transmit data out of the MP modem.)
DB9 female connector
1. Data Carrier Detect (DCD)
1 5
6 9
Serial Host
Main RF
USB Host GPS
Space logic 0
Transmission
region
Mark logic 1
Space logic 0
Transmission
region
Mark logic 1
˝
RS-232-C
Driver
RS-232-C
Receiver
+15 V
+5 V
-5 V
-15 V
+15 V
+3 V
-3 V
-15 V
2 V
noise margin