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The first two-way satellite text-only device (TSTD) was the Magellan GSC-100 introduced in 1998. The GSC-100 was a market failure, and sales and production stopped a few years later. In 2011, many lighter, second-generation TSTDs came to market, including the BriarTek CerberLink and the DeLorme inReach.

All second-generation TSTDs use the Iridium satellite system described in Part 1 of this series. TSTDs are typically lighter and cheaper than the satellite phones described in Part 2. All the information in this series comes from vendor web sites and online reviews, except for the "Personal experience" sections.

TSTDs are different from one-way satellite text-only devices like the SPOT Satellite GPS Messenger. TSTDs can both send and receive text messages, including confirmation that your message got through.

All TSTDs include GPS receivers, and can send your position on demand or on schedule in tracking mode, or in a text message.

The market has further specialized into two kinds of TSTDs:

  • Standalone TSTDs don’t need any other devices for full functionality.
  • Dual-mode TSTDs can operate standalone for limited texting, tracking, and emergency notification, but need a paired device for full functionality, typically a smart phone.


  • Introduction
  • Paired Devices
  • TSTD service plans
    • Example operating costs
  • Battery life
  • Dust and water protection
  • Rent versus buy
  • Patent issues
  • Summarizing reviews and comments
  • Criteria for inclusion
  • Magellan GSC-100 (Orbcomm)
  • BriarTek CerberLink
    • Operating Costs
  • DeLorme inReach PN-60w
    • Operating Costs
  • DeLorme inReach SmartPhone
    • Operating Costs
  • GeoPro Messenger
    • Online review summary
    • Operating Costs
  • NAL SHOUT Nano
    • Online review summary
    • Operating Costs
  • NAL SHOUT ts
    • Online review summary
    • Operating Costs
  • PIEPS Globalfinder Iridium
    • Online review summary
    • Operating Costs
  • Yellowbrick 3 Standard
    • Operating Costs
  • Important Physical Specifications
  • Important Features
  • Sample Pricing
    • Narrowing the field: Lightest Standalone
    • Narrowing the field: Lightest Dual-mode
    • Lightest Paired Devices
    • Narrowing the field: Most reliable
    • Which device would I choose?
    • Satellite phones versus TSTDs
  • Which would I choose: Satellite phone or TSTD?

# WORDS: 4320
# PHOTOS: 10

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