Asterisk channel driver for Quectel and SimCOM modules

See original README of this project.

---

Supported modules:

• Quectel EC25-E,
• SimCOM SIM7600G-H,
• SimCOM SIM900 (analog input/output, see here for more details),
• SimCOM SIM800C (analog input/output),
• SimCOM A7670E (analog input/output, see here for more details).

Changes

General

• Minimal supported Asterisk version is 16 now.

• Using JSON-formatted channel variables.

  One may use JSON_DECODE function in dialplan in order to extract required field.

  • All QUECTEL* variables are wrapped into one JSON-formatted QUECTEL variable.

  • For SMS reporting SMS JSON-formatted variable is defined.

    [incoming-sms]
    exten => sms,1,NoOp(SMS from device ${JSON_DECODE(QUECTEL,name)})
    same => n,Set(SMS_TXT=${JSON_DECODE(SMS,msg)})
    same => n,GotoIf($[${EXISTS(${SMS_TXT})}]?smstxt:smsempty)
    same => n(smstxt),Verbose(2, [${JSON_DECODE(QUECTEL,name)}] Incoming SMS from ${CALLERID(num)} [${JSON_DECODE(SMS,ts)}]: ${SMS_TXT})
    same => n,Goto(smsbye)
    same => n(smsempty),Verbose(2, [${JSON_DECODE(QUECTEL,name)}] Empty incoming SMS from ${CALLERID(num)})
    same => n(smsbye),Hangup

  • For USSD rporting USSD JSON-formatted variable is defined.

    [incoming-ussd]
    exten => ussd,1,NoOp(USSD from device ${JSON_DECODE(QUECTEL,name)})
    same => n,Set(USSD_TXT=${JSON_DECODE(USSD,ussd)})
    same => n,Verbose(2, [${JSON_DECODE(QUECTEL,name)}] Incoming USSD [${JSON_DECODE(USSD,type_description)}]: ${USSD_TXT})
    same => n,Hangup

  • For reporting REPORT JSON-formatted variable is defined.

    [incoming-report]
    exten => report,1,NoOp(Report from device ${JSON_DECODE(QUECTEL,name)})
    same => n,Set(REPORT_SUBJECT=${JSON_DECODE(REPORT,subject)})
    same => n,Set(REPORT_DIRECTION=${JSON_DECODE(REPORT,direction)})
    same => n,Set(REPORT_SUCCESS=${JSON_DECODE(REPORT,success)})
    same => n,Set(REPORT_JSON=${JSON_DECODE(REPORT,report)})
    same => n,Set(REPORT_INFO=${JSON_DECODE(REPORT_JSON,info)})
    same => n,GotoIf($[${REPORT_SUCCESS} = 1]?reportsuccess:reportfail)
    same => n(reportsuccess),Verbose(2,${JSON_DECODE(QUECTEL,name)} - ${REPORT_SUBJECT} - ${REPORT_DIRECTION} - ${CALLERID(num)} - ${REPORT_INFO})
    same => n,Goto(reportbye)
    same => n(reportfail),Verbose(1,${JSON_DECODE(QUECTEL,name)} - ${REPORT_SUBJECT} - ${REPORT_DIRECTION} - ${CALLERID(num)} - ${REPORT_INFO})
    same => n,Goto(reportbye)
    same => n,Hangup

  • Renamed and reimplemented dialplan functions (applications).

    • QuectelStatus application renamed to QUECTEL_STATUS function.

      same => n,Set(QSTATUS=${QUECTEL_STATUS(quectel0)})
      same => Verbose(2,Device status: ${QSTATUS})

    • New QUECTEL_STATUS_EX function.

      Returns device status as JSON.

      same => n,Set(QQSTATUS=${QUECTEL_STATUS_EX(quectel0)})
      same => Verbose(2,Extended device status: ${QQSTATUS})

    • QuectelSendSms application renamed to QUECTEL_SEND_SMS one.

    • QuectelSendUssd application renamed to QUECTEL_SEND_USSD one.

Configuration

• quectel_uac option renamed to uac and it's a on/off/ext switch now.

  alsadev option is also defaulted to hw:Android (when uac=on) or hw:0 (when uac=ext).

• New multiparty option (on/off).

  Ability to handle multiparty calls wastly complicates audio handling. Without multiparty calls audio handling is much simpler and uses less resources (CPU, memory, synchronization objects). I decided to turn off multiparty calls support by default. You can enable it but remember that multiparty calls were never working in UAC mode and even in TTY (serial) mode this support should be considered as unstable. When mutliparty is off all multiparty calls are activley rejected.

• dtmf option is a on/off switch now.

  DTMF detection is now performed by module itself (AT+QTONEDET or AT+DDET command).

• New dtmf_duration option.

  Duration in miliseconds of generated DTMF.

• New msg_direct option (none/on/off).

  Specify how to receive messages (AT+CNMI command):

  value	description
  none	do not change
  on	messages are received directly by +CMT: URC
  off	messages are received by AT+CMGR command in response to +CMTI URC

• New msg_storage option (auto/sm/me/mt/sr).

  Setting prefered message storage (AT+CPMS command):

  value	description
  auto	do not change
  sm	(U)SIM message storage
  me	mobile equipment message storage
  mt	same as me storage
  sr	SMS status report storage location

• New msg_service option (-1/0/1).

  Selecting Message Service (AT+CSMS command):

  value	description
  -1	do not change
  0	SMS AT commands are compatible with GSM phase 2
  1	SMS AT commands are compatible with GSM phase 2+

• New moh option (on/off).

  Specify hold/unhold action:

  value	description
  on	play/stop MOH
  off	disable/enable uplink voice using AT+CMUT command

• txgain and rxgain options reimplented.

  • TX/RX gain is performed by module itself.

    This channel driver just sends `AT+QMIC`/`AT+QRXGAIN` (`AT+CMICGAIN`/`AT+COUTGAIN` for *SimCOM* module) commands.
    

  • Default value is -1 now - use current module setting, do not change gain.

  • Range: 0-65535 or 0-100%.

    See also quectel autio gain tx and quectel audio gain rx commands below.

• New query_time option (on/off).

  value	description
  on	ping module with AT+QLTS (Quectel) or AT+CCLK (SimCOM) command
  off	ping module with standard AT command

• New slin16 option (on/off).

  Enable/disable 16kHz audio (default is 8kHz).
  Currently only SimCOM SIM7600X module handles 16kHz audio.

• New qhup option (on/off).

  For Quectel modules hang up calls using AT+QHUP (Hang up Call with a Specific Release Cause) or standard AT+CHUP (Hang up Voice Call) command.

• New dsci option (on/off).

  For Quectel modules ccinfo (AT+QINDCFG="ccinfo" command) notifications are used by default. You can switch back to (less efficient) dsci (AT^DSCI command) notifications if your module does not support ccinfo notifications.

• Removed disablesms option.

• smsdb option in [general] section defaulted to :memory:

  Internal SQLite3 database is stored in memory by default now.
  You can still put database into a file by specyfying its full path (not recommended).

  See also: SQLIte3: In-Memory Databases.

• New smsdb_backup option in [general] section.

  Path to backup of SMS database created via quectel sms db backup command (see below).

Commands

• simcom is an alias of quectel commands now.

  You may type simcom… command instead of quectel… one. For example quectel show device status command is equivalent of simcom show device status one.

• More SMS commands.

  quectel sms <device> <number> <msg>… command renamed to quectel sms send <device> <number> <msg>….

  Additional commands:

  • quectel sms list received unread <device>

  • quectel sms list received read <device>

  • quectel sms list all <device>

  • quectel sms delete received read <device>

  • quectel sms delete all <device>

  • quectel sms delete <device> <idx>

  • quectel sms direct on <device>

  • quectel sms direct off <device>

  • quectel sms direct auto <device>

  • quectel sms db backup

    Backup of SMS database. Path to backup file is specified in configuration file via smsdb_bakup general option.

• Additional fields in show device status command.

  Added Access technology, Network Name, Short Network Name, Registered PLMN, Band and Module Time fields:

      -------------- Status -------------
  Device                  : quectel0
  State                   : Free
  Audio UAC               : hw:Android
  Data                    : /dev/ttyUSB2
  Voice                   : Yes
  SMS                     : Yes
  Manufacturer            : Quectel
  Model                   : EC25
  Firmware                : EC25EXXXXXXXXXX
  IMEI                    : YYYYYYYYYYYYYYY
  IMSI                    : ZZZZZZZZZZZZZZZ
  GSM Registration Status : Registered, home network
  RSSI                    : 22, -69 dBm
  Access technology       : LTE
  Network Name            : Xxxxx
  Short Network Name      : Yxxxx
  Registered PLMN         : 26006
  Provider Name           : Zxxxxxx
  Band                    : LTE BAND 3
  Location area code      : 0000
  Cell ID                 : AAAAAAA
  Subscriber Number       : Unknown
  SMS Service Center      : +99000111222
  Module Time             : 2000/01/01,00:00:00+08,1
  Tasks in queue          : 0
  Commands in queue       : 0
  Call Waiting            : Disabled
  Current device state    : start
  Desired device state    : start
  When change state       : now
  Calls/Channels          : 0
      Active                : 0
      Held                  : 0
      Dialing               : 0
      Alerting              : 0
      Incoming              : 0
      Waiting               : 0
      Releasing             : 0
      Initializing          : 0
  

  Some of theese fields are constantly updated via act and csq notifications (see AT+QINDCFG command).

  Additional fields in (JSON-formatted) QUECTEL variable are also defined:

  • network_name,

  • short_network_name,

  • privider,

  • plmn,

  • mcc,

  • mnc,

  • iccid.

    PLMN (Public Land Mobile Network Code) combines MCC (Mobile Country Code) and MNC (Mobile Network Code).

    SMS Service Center is now decoded from UCS-2.

• Additional fields ins quectel show device settings command.

  Displaying new configuration options:

      ------------- Settings ------------
  Device                  : quectel0
  Audio UAC               : hw:Android
  Data                    : /dev/ttyUSB2
  IMEI                    : 
  IMSI                    : 
  Channel Language        : en
  Context                 : quectel-incoming
  Exten                   : 
  Group                   : 0
  RX gain                 : -1
  TX gain                 : -1
  Use CallingPres         : Yes
  Default CallingPres     : Presentation Allowed, Passed Screen
  Disable SMS             : No
  Message Service         : 1
  Message Storage         : ME
  Direct Message          : On
  Auto delete SMS         : Yes
  Reset Quectel           : No
  Call Waiting            : auto
  Multiparty Calls        : No
  DTMF Detection          : No
  Hold/Unhold Action      : Mute
  Query Time              : Yes
  Initial device state    : start
  

• New quectel audio commands:

  These are just wrappers around few audio-related AT commands:

  command	AT command
  quectel audio mode	AT+QAUDMOD
  quectel audio gain tx	AT+QMIC
  quectel audio gain rx	AT+QRXGAIN
  quectel audio loop	AT+QAUDLOOP

• New quectel uac apply command:

  This command just sends AT+QPCMV=0 and AT+CFUN=1,1 commands. It is helpful if you change TTY mode to UAC or vice versa.

Internal

• UCS-2 encoding is mandatory now.

• Call handling is based on automatic call status contifications.

  • For Quectel modules ccinfo (default) or dsci notifications are used.
  • For SimCOM modules clcc notifications are used.

• Improved/extended AT commands response handler.

  Changes required to properly handle AT+CMGL command response. This command is now executed at initialization stage in order to receive unread messages.

• Simplyfying audio handling (when mutliparty is off, see above) in UAC and TTY mode.

  • Using less resources.
  • Much simpler error handling.
  • More debug messages.
  • Reorganized, improved and simplified code.

• Fixed USSD sending/receiving.

• Getting ICCID from SIM card.

  ICCID: Integrated Circuit Card Identifier.

  It is possible to address device by ICCID (j: prefix):

  exten => s,n,Dial(Quectel/j:898600700907A6019125/+79139131234)
  

• Code (re)formatted by clang-format utility.

  Links:

  • ClangFormat,
  • Edit C++ in Visual Studio Code -- Code formatting.

• Using CMake build system.

• Improved debug messages.

  • Non-printable characters are C escaped using custom function based on ast_escape_c:

    ```
    DEBUG[11643]: at_read.c:93 at_read: [quectel0] [1][\r\n+QIND: "csq",27,99\r\n]
    DEBUG[11654]: at_read.c:93 at_read: [quectel0] [1][\r\n+CPMS: 0,25,0,25,0,25\r\n\r\nOK\r\n]
    DEBUG[11654]: at_read.c:93 at_read: [quectel0] [1][\r\n+QPCMV: 0,2\r\n\r\nOK\r\n]
    DEBUG[13411]: at_queue.c:181 at_write: [quectel0] [AT+QSPN;+QNWINFO\r]
    ```
    

  • Using Unicode characters in log messages.

    Mostly arrows are used:
    
    ```
    DEBUG[20486]: src/at_queue.c:128 at_queue_add: [quectel0][AT+QLTS=1] ↵ [OK][AT+QLTS=1\r] after head
    DEBUG[20486]: src/at_queue.c:336 at_queue_run: [quectel0][AT+QLTS=1] → [AT+QLTS=1\r]
    DEBUG[20486]: src/at_response.c:2718 show_response: [quectel0][AT+QLTS=1] ← [+QLTS][+QLTS: "2000/01/01,00:00:00+00,1"]
    DEBUG[20486]: src/at_response.c:2718 show_response: [quectel0][AT+QLTS=1] ← [OK][OK]
    DEBUG[20486]: src/at_response.c:246 at_response_ok: [quectel0][AT+QLTS=1] ✓
    DEBUG[20486]: src/at_queue.c:72 at_queue_remove: [quectel0][AT+QLTS=1] ↳ [OK] tasks:0 
    
    ```
    

• Redesigned SMS database.

• Using modern serial port locking methods:

  • ioctl(fd, TIOCGEXCL, &locking_status) and ioctl(fd, TIOCEXCL),
  • flock(fd, LOCK_EX | LOCK_NB).

• Using thread pools and task processors:

  Reading and processing modem responses in separate threads. You may see basic statistics of used thread pools and task processors via core show taskprocessors like chan-quectel command.

  Asterisk*CLI> core show taskprocessors like chan-quectel
  
  Processor                                                               Processed   In Queue  Max Depth  Low water High water
  chan-quectel/pool                                                           16874          0          1        450        500
  chan-quectel/pool-control                                                   33749          0          1        450        500
  chan-quectel/simcom7600-00000051                                            39171          0          4        360        400
  
  3 taskprocessors
  

• Many small optimizations.