Filling the Gap When AT&T Discontinues 2G GSM

AT&T’s 2G GSM network is going away in January of 2017. The company has stopped certifying new 2G GSM applications for deployment and is no longer provisioning new SIMs for 2G GSM devices and applications. For developers working on new products the message is clear—look elsewhere—but for those with GSM products already out there, it’s time to start planning for a replacement.
There are a number of ways to incorporate cellular modems into a new or redesigned product. These include chip-down chipset, external, and solder-in modems. One of the quickest, easiest, and most cost effective options is a pre-certified, plug-in, embedded modem, a solution that eliminates a chunk of the design process as well as cost and delay for achieving certification. (Not an issue, of course, if you’ve got plenty of time and money.)
There are a variety of plug-in modems out there, and some of your considerations in choosing will include size, voltage requirements, form factor, operating mode, port configuration, and development support. Now here comes the commercial, so if you already know all you care to about plug-in modems, this might be a good time to go make a sandwich.
No surprise, but we think NimbeLink’s Skywire® CDMA Plug-in Cellular Modem is a great option for M2M applications. For starters, as a CDMA device it is not affected by AT&T’s discontinuation of 2G GSM. And it’s precertified, which can save time and reduce risk in developing new or redesigned applications.
Skywire uses the same Telit CE910-DUAL chip as some other plug-in modems you can buy, but compared, for example, to the Janus CDMA910CF plug-in modem:

  • The Skywire modem is significantly smaller at 29mm x 33mm x 6.5mm vs. the Janus modem at 63.5mm x 35.6mm x 11.3mm. Skywire’s compact design is ideal for development of today’s compact devices.
  • Skywire supports a wide input range of voltages—1.65V to 5.5V—for the UART and control signal. Janus requires the relatively uncommon 2.85VDC and may need the addition of level shifters, which add to cost, and complexity and can potentially slow development.
  • Skywire is readily available through Digi-Key, which offers immediate shipment and the world’s largest selection of electronic components.

The Skywire plug-in modem uses a standard form factor and 1xRTT CDMA operating mode to help minimize hardware and network costs, and a U.FL port to ensure antenna flexibility. It is available with bundled CDMA 1xRTT data plans from leading carriers, allowing developers to add fully compliant cellular connectivity without having to apply for certification. Future versions will support GSM and LTE.
Skywire is available with a complete development kit that includes the cellular modem itself, baseboard, antenna, power supply, debug cables, and cellular service plan. The Skywire baseboard is an Arduino shield, allowing direct connection to an Arduino microcontroller.