SIMCom A7682E CLI

Small C++ command-line tool for talking to an A7682E modem over its AT command control port.

The current goal is manual configuration and monitoring from a terminal. The code is split into a reusable serial/AT layer so it can later grow into a DBus-backed modem manager.

Modem Port Layout

From doc/A76XX Series_Linux_USB_Application Note_V1.00.pdf:

• /dev/ttyUSB0: diagnostic output
• /dev/ttyUSB1: AT command control port
• /dev/ttyUSB2: PPP modem/data port
• /dev/ttyUSB3: NMEA port when GNSS is enabled

This tool defaults to /dev/ttyUSB1.

Build

make

The binary is written to bin/simcom_cli.

Usage

High-level commands:

./bin/simcom_cli info
./bin/simcom_cli get signal
./bin/simcom_cli get operator
./bin/simcom_cli get network-mode
./bin/simcom_cli set cmee 2
./bin/simcom_cli set apn 1 internet
./bin/simcom_cli set operator auto
./bin/simcom_cli set network-mode lte
./bin/simcom_cli set reset
./bin/simcom_cli set usbnetmode 1

Raw AT mode still works:

./bin/simcom_cli AT+CSQ
./bin/simcom_cli +CPIN?
./bin/simcom_cli raw AT+COPS?

Interactive shell:

./bin/simcom_cli --interactive

Interactive shell notes:

• high-level commands such as info, get signal, and set cmee 2 work in the shell
• raw AT commands such as AT, ATI, AT+CSQ, and AT+CEREG? also work
• commands starting with +, $, &, or * are automatically prefixed with AT
• local shell commands use a leading :
• :help shows interactive help
• :raw on or :raw off toggles raw line printing
• :timeout 5000 changes the per-command timeout
• :quit exits

Monitor unsolicited modem output:

./bin/simcom_cli --monitor

This mode just prints incoming modem lines with timestamps until Ctrl-C.

Named Commands

info runs a small status bundle:

• manufacturer
• model
• firmware
• IMEI
• SIM state
• signal quality
• operator
• EPS registration
• packet attach state
• PDP contexts
• modem functionality state

get <name> currently supports these aliases:

• id, identity
• manufacturer, model, firmware
• imei, imsi
• sim, pin
• signal, csq
• operator, cops
• reg, network, eps-reg, cereg
• ps-reg, cgreg
• cs-reg, creg
• attach, cgatt
• pdp, contexts, apn, cgdcont
• active-contexts, cgact
• clock, cclk
• errors, cmee
• functionality, fun, cfun
• activity, cpas
• network-mode, netmode, cnmp

set <name> <value...> supports:

• generic AT setters such as set cmee 2 -> AT+CMEE=2
• set apn <cid> <apn> [pdp_type]
• set operator auto -> AT+COPS=0
• set network-mode <auto|gsm|lte> -> AT+CNMP=<...>
• set reset -> AT+CFUN=1,1
• set usbnetmode <0|1> -> AT$MYCONFIG="usbnetmode",<value>
• set dialmode <0|1> -> AT+DIALMODE=<value>

For unusual commands or exact quoting requirements, use raw AT mode directly.

Supported Human-Readable Parsers

The CLI currently decodes these common status/configuration commands:

• ATI
• AT+CGMI
• AT+CGMM
• AT+CGMR
• AT+CGSN
• AT+CIMI
• AT+CPIN?
• AT+CSQ
• AT+CREG?
• AT+CGREG?
• AT+CEREG?
• AT+COPS?
• AT+CGATT?
• AT+CGACT?
• AT+CGDCONT?
• AT+CCLK?
• AT+CMEE?
• AT+CFUN?
• AT+CPAS
• AT+CNMP?

Unknown commands still work; the CLI falls back to printing the modem's raw response lines.

Notes

• The tool currently handles classic line-oriented AT responses ending in OK, ERROR, +CME ERROR, +CMS ERROR, CONNECT, NO CARRIER, NO ANSWER, or BUSY.
• It is not yet a full URC-aware modem manager. That is the next logical step once the manual CLI workflow is stable.
• For clearer errors, AT+CMEE=2 is useful during manual sessions.