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

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.

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

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

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+

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

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

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>

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 channel variables are also defined:

QUECTELNETWORKNAME,
QUECTELSHORTNETWORKNAME,
QUECTELPROVIDER,
QUECTELPLMN,
QUECTELMCC,
QUECTELMNC,
QUECTELICCID.

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

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`

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)
```
Additional variable QUECTELICCID is also defined.
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

Using modern serial port locking methods:
- ioctl(fd, TIOCGEXCL, &locking_status) and ioctl(fd, TIOCEXCL),
- flock(fd, LOCK_EX | LOCK_NB).
Many small optimizations.

huajijam/asterisk-chan-quectel

Asterisk channel driver for Quectel and SimCOM modules

Changes

Configuration

Commands

Internal