Communicate With The Cellular or POTS Modem

Interfacing with the cellular modem is only available via CLI.

Usage  
mmcli [OPTION?] Control and monitor the ModemManager.
Option Description
-h, --help Show help options
--help-all Show all help options
--help-manager Show manager options
--help-common Show common options
--help-modem Show modem options
--help-3gpp Show 3GPP related options
--help-cdma Show CDMA related options
--help-simple Show Simple options
--help-location Show Location options
--help-messaging Show Messaging options
--help-voice Show Voice options
--help-time Show Time options
--help-firmware Show Firmware options
--help-signal Show Signal options
--help-oma Show OMA options
--help-sim Show SIM options
--help-bearer Show bearer options
--help-sms Show SMS options
--help-call Show call options
Application Options Description
-v, --verbose Run action with verbose logs
-V, --version Print version
-a, --async Use asynchronous methods
--timeout=[SECONDS] Timeout for the operation
2 (UTRAN) 3G
7 (E-UTRAN) 4G
5G SA
13 (E-UTRA-NR dual connectivity) 5G NSA

Internal Modem (POTS)

The OM2200-10G-M-DDC-L is fitted with an internal POTS modem. The POTS modem can be used to obtain CLI access to the OM, which allows users to dial into a device and obtain a command prompt by using the modem. The modem is configured at the WebUI, Config Shell or CLI. Configuration is discussed later in this topic.

The modem is connected via the RJ15 cable at the RJ15 port at the rear, when connecting the cable you will hear or feel a click when it is correctly inserted.

The POTS modem supports the following modes:

  • Dial-In Only - In this mode the device will not dial-out to other modems.

  • Management Console Only - On successful connection, only a console (login prompt and shell access) is active. The modem is not a network interface, it will not carry IP traffic.

Configuring the POTS Modem (OM2200-10G-M-L)

POTS modem entities are detected and added to the config when the device is booted and therefore cannot be added or deleted later.

The internal POTS modem has the following configurable options:

Configuration Modem Behavior
dialin mode enabled or disabled The modem will listen for connections and automatically answer, providing a serial console to the requester.
Baud rate The baud rate to use between the modem and the internal serial port.
Custom AT Command Sequence This is a single-line, multi-command string to use to initialize the modem with specific behavior.
Configuration via the WebUI

Configure > Network Connections > Network Interfaces

POTS Modem configuration listed at the above table are accessible from the Network Interfaces page. The configuration options appear below the other network interfaces in the list, the modem can be enabled in “dialin” mode or disabled. Clicking the Edit link navigates to the modem detail page if further configuration is required.

POTS Configuration via the Config Shell

The 'pots_modems' entity can be modified by Config Shell. POTS modem entities cannot be added or deleted after the boot sequence because they are detected and added to the config when the device is booted.

Config Shell Command Examples

The fields listed in the configurable options table can be configured via the Config Shell:

Required Action Command Example
Show the POTS modem configuration show pots_modem modem01
Enable the POTS modem edit pots_modem modem01 mode dialin
Disable the POTS modem edit pots_modem modem01 mode disabled
Set the modem baud rate edit pots_modem modem01 baud 38400
Set an AT command sequence edit pots_modem modem01 command_sequence 'AT+CGI=09'
Clear the AT command sequence edit pots_modem modem01 command_sequence ''

Note:    Supported POTS modem baud rates are 2400, 4800, 9600, 19200, or 38400.

Custom AT Command Sequence

The command sequence is a single-line, multi-command string to use to initialize the modem with specific behavior. It looks like a standard AT command, for example: AT+MSv32.

  • The initial AT can be entered or omitted.

  • Multiple commands can be entered separated by semicolons ';' eg. AT+MSv32;&v

  • There is no requirement to add the prefix AT for subsequent commands after the semicolon.

  • Some commands expect a value to be entered and require an = to be present eg. AT+GCI=09

  • Spaces are not allowed in the command sequence.

Example Custom AT Commands

Required Action Command Example
Show the POTS modem configuration show pots_modem modem01
Enable the POTS modem edit pots_modem modem01 mode dialin
POTS Configuration via the CLI

CLI access to the (OM2200-10G-M-L) can be obtained using a POTS (aka dialup modem) connection. Connection requires a terminal program that can interact with a dialup modem and support VT102 terminal emulation. On Linux, ‘tip’ is commonly used. On windows, PuTTY is available.

When a dialup connection with the (OM2200-10G-M-L) is established, a login prompt presented and you can proceed exactly as if connected to the management console using a direct connection.

Note: If the modem session is ended, the console session will also end. Users are required to login again after starting a new modem call.

Logging

  • At modem start-up, the following log is printed to syslog:
    Jul 26 02:37:22 (OM2200-10G-M-L) systemd[1]: Started Serial Getty on modem01.

  • Mgetty logs are redirected to rsyslog, which include the logging of what is received and sent from the pots modem.

No other modem logs are output.