Chapter 2 – Installation
Multi-Tech Systems, Inc. MultiModem EDGE USB Wireless Modem User Guide 9
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

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 indicates the 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 EDGE wireless modem are published in a separate Reference Guide included on
the MultiModem CD and posted on the Multi-Tech web site.