Documentation › AT commands
AT command reference
Multiple AT commands can be typed on a single line. Spaces between commands are allowed, but not within commands
(ATS0=1 X1 Q0 is fine; ATS 0= 1 is not). Commands taking a string argument (e.g.
AT$SSID=, AT$TTY=) consume everything that follows, so no command may follow
them.
Basic commands
| Command | Details |
|---|
+++ | Online escape code: one second pause, three +, another one second pause — returns to local command mode. |
A/ | Repeats the last command entered. Do not type AT or press Enter. |
AT | The attention prefix preceding all commands except A/ and +++. |
AT? | Displays a help cheatsheet. |
ATA | Force the modem to answer an incoming connection. |
ATE? / ATEn | Command-mode echo. E0 off, E1 on. |
ATH | Hang up the current connection. |
ATI | Display network status: build date, WiFi/call state, SSID, RSSI, IP, bytes transferred. |
ATO | Return online (use with +++ to toggle command/online modes). |
ATQ? / ATQn | Result codes. Q0 display, Q1 suppress (quiet). |
ATV? / ATVn | Result codes as words (V1) or numbers (V0). |
ATX? / ATXn | Result code verbosity. X0 basic (CONNECT, NO CARRIER), X1 extended (speed / connect time). |
ATZ | Reset the modem. |
ATRD / ATRT | Display current UTC date/time from NIST. Requires WiFi and no active call. |
Connection & dialling
| Command | Details |
|---|
ATC? / ATCn | Query/change WiFi connection status. 0 = not connected, 1 = connected. ATC0 disconnects, ATC1 connects. |
ATDT[+=-]host[:port] | Establish a TCP connection to host/IP (default port 23, Telnet). Speed-dial by alias or 7 identical digits. A leading +/=/- overrides the ATNET setting for the call (+ fake Telnet, = real Telnet, - no Telnet). |
ATDSn | Calls the host in speed dial slot n (0-9). |
ATS0? / ATS0=n | Rings before auto-answer. S0=0 = don't answer. |
ATS2? / ATS2=n | ASCII code of the online escape character (default 43 = +). 128-255 disables. |
AT&Zn? / AT&Zn=host[:port],alias | Store up to 10 speed-dial entries. Example: AT&Z2=bbs.example:6400,bbs → ATDS2 / ATDTbbs. |
AT&R? / AT&R=server pwd | Password required for incoming connections (3 tries in 60 s). |
Web & TLS
| Command | Details |
|---|
ATGEThttp://host[/page]
ATGEThttps://host[/page] | Fetch and display a web page, then close. https is TLS-terminated by the modem. |
AT$CA? / AT$CA= / AT$CA- | TLS CA management. ? reports the stored CA size (bytes), = uploads a CA in PEM form (end with a line containing only .), - deletes it. |
AT$CV? / AT$CVn | TLS certificate verification. 0 = off (accept any cert), 1 = on. AT$CV1 returns ERROR unless a CA is stored. |
WiFi & network
| Command | Details |
|---|
AT$SSID? / AT$SSID=ssid | Query/change the SSID (case sensitive, max 32 chars). Set empty to clear. |
AT$PASS? / AT$PASS=pwd | Query/change the WiFi password (case sensitive, max 64 chars). Set empty to clear. |
AT$SCAN | Scan for nearby 2.4 GHz WiFi networks. One access point per line as <index> <ssid> (1-based, de-duplicated by SSID, hidden SSIDs skipped), then OK. The index drives a numbered menu fed back via AT$SSID=. |
AT$MDNS? / AT$MDNS=name | mDNS network name. With a non-zero TCP port set, reach it via telnet name.local port. |
AT$SP? / AT$SP=n | TCP server port to listen on (0 = disabled). |
ATNET? / ATNETn | Telnet mode. 0 = off, 1 = real Telnet, 2 = fake Telnet. |
Serial, settings & NVRAM
| Command | Details |
|---|
AT$SB? / AT$SB=n | Baud rate: 110, 300, 450, 600, 710, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 76800, 115200. Must match your terminal. |
AT$SU? / AT$SU=dps | Data bits (5-8), parity (N/O/E), stop bits (1-2). Default 8N1. |
AT&K? / AT&Kn | Flow control: &K0 off, &K1 hardware (CTS/RTS). |
AT&D? / AT&Dn | DTR-inactive handling: &D0 ignore, &D1 command mode, &D2 end call, &D3 reset. |
AT&F | Reset NVRAM and current settings to defaults (SSID, password, speed dials included). |
AT&Vn | Display current (&V0) or stored (&V1) settings. |
AT&W | Save current settings to NVRAM. |
AT$AE? / AT$AE=cmd | The AT command line executed at startup. |
AT$W? / AT$W=n | Startup wait. $W=0 no wait, $W=1 wait for Enter. |
Telnet (options)
| Command | Details |
|---|
AT$AYT | Send a Telnet "Are You There?" if connected to a Telnet remote. |
AT$BM? / AT$BM=msg | Message returned to an incoming connection while busy. |
AT$TTL? / AT$TTL=location | Telnet SEND-LOCATION value (default "Computer Room"). |
AT$TTS? / AT$TTS=WxH | Telnet NAWS window size (default 80×24). |
AT$TTY? / AT$TTY=type | Telnet TERMINAL-TYPE value (default "ansi"). |
Reproduced from the
README.md
(§ Command reference — authoritative, up-to-date version on GitHub).
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