Chapter 1 – Description & Specifications
Multi-Tech Systems, Inc. MultiModem GSM/GPRS User Guide 12
LED Indicators
TD. Transmit Data. Lit when modem is transmitting data.
RD. Receive Data. Lit when modem is receiving data.
CD. Carrier Detect. Lit when data connection has been established.
LS. Line Status. Continuous “on” state indicates that the wireless modem is not registered
on the network.
Flashing state indicates registration on network.
Off state. Modem is off (not ready) or in download mode.
TR. Terminal Ready. Commonly called “Data Terminal Ready.” This is a readiness signal from
the PC.
PWR. Power. Indicates presence of DC power when lit.
RS232 15-Pin Connector Pinout
10
11
6
15
15
PIN EIA CCIT Designation
1 DCD 109 Data Carrier Direct
6 RX 104 Receive Data (out)
2 TX 103 Transmit Data
8 DTR 108.2 Data Terminal Ready
9 GND Signal Ground
7 DSR 107 Data Set Ready
12 RTS 105 Request to Send
11 CTS 106 Clear to Send
RS
232
13 RI 125 Ring Indicator
4 MICROPHONE (+)
5 MICROPHONE (-)
10 SPEAKER (+)
Audio
15 SPEAKER (-)
Boot 3 BOOT For factory use only.
Reset 14 RESET To reset, connect to GND
momentarily. Open for normal
operation.