Use ZTerm to Get Your Mac to Talk to MultiModem GPRS


2 min read

This week I had a chance to test drive MultiTech’s MultiModem GPRS, an inexpensive industrial modem that connects to your USB port and serves as a GPRS modem or GSM device for your computer.

I couldn’t find a step by step guide explaining how to set up MultiModem with a local terminal for testing on the Mac, and it took me a little while to figure it out by trial and error. So for the record and to save you some time, here’s how to talk to your MultiModem with a terminal program — ZTerm.

  1. Set up and install MultiModem.

This part is easy. First, download the Mac drivers from MultiTech’s website and install them. Then insert a SIM card into the modem (yes, use the one from your phone) and connect the modem to the USB port.

  1. Download ZTerm and configure it.

Download and install ZTerm, start it, and configure it as follows:

On Settings > Modem Preferences select MTCBA from the list of connections.

and on Settings > Connection set the data rate to 115200. Make sure that the rest of the settings are the same as on the screenshot (they should be by default).

  1. Playtime

Now you’re ready to roll. The MultiModem ships with comprehensive documentation of modem commands, here are some simple ones to try out right away:

  • AT+CGMI[enter] to query the manufacturer
  • AT+CGMM to query the model identification
  • AT+CMGS=”[phone number]”[enter] followed by a message, terminated by CTRL-Z to send an SMS message

What we're doing.