
Chapter 2 – Installation
Interfaces
The Wireless MultiModem has several interfaces:
•LED function indicating operating status
•External antenna (via SMA connector)
•Serial and control link (via USB connector)
•Microphone and speaker (via handset jack)
•SIM card holder
LEDs
  | 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.  | 
AT Command Reference Guides
AT commands for the GPRS USB wireless modem are published in a separate GPRS AT Commands Reference Guide included on the MultiModem CD and posted on the 
9  |