AT Protocol

Overview

Echo

Echoing is a common feature which is enabled when talking with devices using the AT command protocol. An important thing to note is the device will echo letters as they are typed into the terminal, not when you press enter. This may have implications when trying to use echo to match a sent command with a response.

AT Result Codes

The following table lists the most commonly used AT result codes:

Result Code (Numerical) Result Code (Textual)
0 OK
1 CONNECT
2 RING
3 NO CARRIER
4 ERROR
5 CONNECT 1200
6 NO DIALTONE
7 BUSY
8 NO ANSWER