Zapcard module

Zaptel PRI/TDM/FXS/FXO cards signalling and data driver. This module can build

• Signalling interfaces (D-channels) on PRI cards
• Audio channels (B-channels) on PRI cards.
• FXO/FXS channels on analog or T1 RBS cards.

Building a D-channel

D-channels are built and managed on request (by API calls), not at startup. The configuration file is read when a request is processed.
The sig parameter of the request MUST indicate an existing section in zapcard.conf (e.g. zaptel1).
The sigchan parameter from the section given by sig MUST indicate a valid channel configured in driver.
An interface opens its channel and starts the worker thread when enabled by the owner. It closes the channel and stop the worker thread when disabled.
NOTE: No check is made if the zaptel channel is in use. If the channel is in use (by other programs or Yate) the D-channel creation won't fail.

Building a B-channel group (voice span)

B-channel groups are built and managed on request (by API calls), not at startup. The configuration file is read when a request is processed.
The voice parameter of the request MUST indicate an existing section in zapcard.conf.
The voicechans parameter from the section given by voice MUST indicate a valid channel (or range of channels) configured in driver.
When a channel is connected (actually involved in a call) the zaptel device associated with it is opened and the worker thread is started. When the channel is disconnected the zaptel device is closed and the worker thread is stopped.
Voice channel creation will fail if:

• The section indicated by the voice parameter is not found in configuration file.
• The voicechans parameter from the span configuration section is invalid.

Building an FXO/FXS group

Same as building B-channels. Due to the fact that an analog channel carry the call signalling, the zaptel device is opened when the channel is reserved.

Additional commands

status

status zaptel spans

Show all zaptel spans

status zaptel channels

Show the status of all zaptel channels used by this module

status zaptel all

Show the status of all zaptel channels in the system

Message handlers

• engine.status show the status of module, zaptel spans or channels

Configuration

Some considerations on the offset parameter:

• Remember: Zaptel is using sequential numbers for available channels.
• The sigchan and voicechans parameters indicate the channel number inside the logical span (group). The offset value is added to each channel number to build the zaptel channel number.
• This parameter was introduced to make it easy to remove zaptel channels from driver: when removed, just change the offset of the remaining channels!

Configuration file: zapcard.conf

 
; This file keeps the configuration of cards using the zaptel driver
; Each section except for 'general' configures a group (span) of zaptel channels
; For now on in this file's terminology a span means a group of circuits mapped
;  to zaptel channels that may belong to different zaptel spans
;
; NOTES:
;  - It is not mandatory to match a group of circuits to a zaptel span
;  - The circuits are not created on load: they are created on demand
;  - It is not possible to mix FXS/FXO circuits in the same group
;  - All circuits belonging to the same group share its settings


[general]
; This section keeps general settings for zaptel module and groups

; format: string: Default data format for analog (FXS/FXO) circuits
; Allowed values are alaw (G711 a-law) or mulaw (G711 mu-law). Defaults to mulaw
; This option can be overriden in span sections
; NOTE: The data format for digital circuits defaults to alaw for E1 and mulaw
;  for T1 and it's negociated by other protocols
;format=mulaw

; idlevalue: integer: The value to fill whenever voice data is missing
; E.g. on incomplete read (less the buffer length) the circuit will fill the rest
;  of the buffer with the value given by this parameter before forwarding it
; Interval: 0..255. Defaults to 255
; This option can be overriden in span sections
;idlevalue=255

; buflen: integer: The length of the buffers used by the data source and consumer
;   created by the circuits
; For data sources this is the length of the buffer used to read data from devices
; Data consumers will use this value multiplied by 4 as a limit of send buffer. Any
;  data exceeding the buffer length will be dropped. The purpose is to avoid driver
;  buffer overrun
; This value can't be 0. Defaults to 160
; This option can be overriden in span sections
;buflen=160

; errormask: integer: Value to AND with the received error byte on E1/T1 interface
; The errors controlled by this mask are 1: RX buffer overrun 2: HDLC Align error
; Maximum value 255
; Defaults to 255 if missing or invalid
; Ignored if type is not E1 or T1
; This option can be overriden in span sections
;errormask=255

; priority: keyword: Default priority of the data service threads (read data and
;  events from Zaptel devices)
; Allowed values: lowest, low, normal, high, highest
; NOTE:
;  - It is a bad idea to set a low priority for anything but testing
;  - Interface (D-channel) circuits' threads are created when the interface is
;    enabled and stopped when disabled/destroyed
;  - Digital voice (E1/T1) circuits' threads are created when the circuit is
;    connected (prepared to be used in an active call) and destroyed when
;    disconnected/destroyed
;  - Analog (FXS/FXO) circuits' threads are created when the circuit is reserved
;    (used) and destroyed when idle(unused)/destroyed
; Defaults to normal
;priority=normal


;[zaptel1]
;This section configures a span (group of circuits) named zaptel1

; type: string: Specify the span signalling type (required)
; Allowed values:
;  E1, T1:  E1/T1 signalling. Circuits belonging to this span can be
;           configured as voice circuits or signalling only (SS7, ISDN etc) circuits
;  FXO:     This group's circuits are telephone sets linked to telephone exchanges
;  FXS:     This group's circuits are telephone exchanges linked to telephone sets
; Defaults to E1 if missing or invalid
; NOTE: Unlike Zaptel terminology, in this file FXO/FXS indicates the signalling of the
;  local end of the line, not the remote's one
;type=E1

; offset: integer: Value to add to each circuit (voice or signalling) number (required)
; This is the offset in the zaptel circuits set of the circuits belonging to this span
; For example, if the span have 2 logical circuits: 1 and 3 and offset is 24 the
;  circuit 1 will use the zaptel channel 25 and circuit 3 will use zaptel channel 27
; There is no default value for this option: circuit/interface creation will be denied
;  if this value is invalid (not an integer or less then 0)
;offset=

; sigchan: integer: The circuit used for signalling (D-channel)
; Numbers greater then circuit count (circuit count defaults to 31 for E1 and
;  to 24 for T1) are not allowed
; Defaults to 16 for E1 and to 24 for T1
; Ignored if type is FXS/FXO
;sigchan=16

; voicechans: string: The range of circuits used for voice (data) transfer or
;  voice and signalling if the type is FXS/FXO
; Circuit intervals may be specified by separating the margins using the '-' character
; Individual circuits or circuit intervals may be separated by '.'
; Duplicate, not strict positive circuit numbers, or circuit numbers greater
;   then circuit count are not allowed. Circuit count defaults to 31 for E1
;   and to 24 for T1. For FXS/FXO spans the channel count is detected from the list)
; E.g. 1-15.17-31 or 1-23 or 1.2.3-15.17.18-30.31
; If missing, will be computed from type (E1: 1-15.17-31, T1: 1-23, FXO/FXS: 1)
;voicechans=1-15.17-31

; dtmfdetect: boolean: Set/reset DTMF detection on each zaptel channel used by
;  a circuit belonging to this span
; If enabled and DTMF detection is not supported by the zaptel driver it will be disabled
; Defaults to enable
;dtmfdetect=enable

; echotaps: integer: The number of taps in the echo canceller used by the circuits
;  belonging to this span
; Set to 0 to disable the echo canceller
; Defaults to 0 if missing or invalid
;echotaps=0

; echotrain: integer: The amount of time (in miliseconds) used to train the echo canceller
; Ignored if echo canceller is disabled
; Defaults to 400
;echotrain=400

; readonly: boolean: Specifies if this is a read only span (signalling and audio data)
; Defaults to no
;readonly=no

; trackhook: boolean: Poll the hook status (only in FXO mode) for devices in parallel
; Defaults to no
;trackhook=no

Example of zapcard.conf

Configuring for E1/T1 usage

The example below configures a digital card with 4 spans.

• span1: T1: channels 12 and 24 are going to be used as signalling (D-Channels) for ISDN or SS7, all other channels are used as B-Channels
• span2: T1: all channels are used for voice transfer
• span3: T1: all channels are used for voice transfer
• span4: E1: default usage: channel 16 is used as D-Channel, all other channels will be used as B-Channels (voice)

[span1-1]
type=T1
offset=0
sigchan=12
voicechans=1-11

[span1-2]
type=T1
offset=12
sigchan=12
voicechans=1-11

[span2]
type=T1
offset=24
voicechans=1-24

[span3]
type=E1
offset=48
voicechans=1-24

[span4]
type=E1
offset=72

Here are some examples of how ysigchan module can use this configuration:

Use channel 12 on span1 to transfer ISDN signalling and channels 1-11 on span1 and channels 1-24 on span2 to transfer audio:
[link1]
type=isdn-pri-net
sig=span1-1
voice=span1-1,span2

OR

Use channel 24 on span1 to transfer SS7 signalling and channels 1-11 on span1, channels 1-24 on span2 and channels 1-24 on span3 to transfer audio:
[link1]
type=ss7-isup
sig=span1-2
voice=span1-1,span2,span3

OR

Use channel 16 on span4 to transfer ISDN signalling and channels 1-11 on span1, channels 1-24 on span2, channels 1-24 on span3, channels 1-15.17-31 on span4 and channels 13-23 on span1 to transfer audio:
[link1]
type=isdn-pri-cpe
sig=span4
voice=span1-1,span2,span3,span4,span1-2

Configuring for TDM/FXO/FXS usage

The example below configures a digital card with 2 spans configured to use TDM signalling and an analog card with 2 FXO channels and 2 FXS channels.
The first span on the digital card is using FXO signalling and the second one is using FXS signalling.

[span1]
type=FXO
offset=0
voicechans=1-24

[span2]
type=FXS
offset=24
voicechans=1-24

[span3-1]
type=FXO
offset=48
voicechans=1

[span3-2]
type=FXO
offset=49
voicechans=1

[span4]
type=FXS
offset=50
voicechans=1,2

Here are some examples of how the analog module can use this configuration:

FXO group using zaptel channels 1..24, 49 and 50
[group1]
type=FXO
spans=span1,span3-1,span3-2

OR

FXO group using zaptel channels 1..24 and 50
[group1]
type=FXO
spans=span1,span3-2

OR

FXS group using zaptel channels 25..48, 51 and 52
[group1]
type=FXS
spans=span2,span4