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AT Commands

Summary

  • AT commands are the text-based command language used to control a modem — cellular modems included — descended from the original Hayes command set developed for dial-up modems in the 1980s.
  • Every command starts with AT (from "ATtention"), and the modem replies with OK, ERROR, or specific data depending on the command.
  • Cellular-specific commands are standardized in 3GPP TS 27.007 and TS 27.005, layered on top of the original ITU-T V.25ter command set.1

Think of AT commands as:

"A modem's own tiny command-line shell — type a command over UART/USB, get a text reply back, no special driver required."

Classic Command Reference

⌕ /
>_

Nothing Found

Sorry, we don't have that command.

Setup

Setup

Figure 1. Setup1

Command Line

Basic Structure of a Command Line

Figure 2. Basic Structure of a Command Line1

Information Responses & Result Codes

Command Line Response

Figure 3. Command Line Response1

Useful Resources

  • 3GPP TS 27.007 — AT command set for User Equipment (UE)
  • 3GPP TS 27.005 — Use of DTE-DCE interface for SMS and CBS
  • ITU-T V.25ter — the original serial asynchronous DCE control command set AT commands descend from

  1. 3GPP. (n.d.). AT command set for User Equipment (UE) (Technical Specification TS 27.007). 3rd Generation Partnership Project. https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1515 ↩↩↩↩