Zaptel PRI Trunk (ZOA1)


This interface enable routing through the ISDN protocol using a PRI

Release notes

Version 3.10 - General deployment
  • Feature: Configurable channel range

Version 3.09 - General deployment
  • Feature: Reset interval configurable

Version 3.08 - General deployment
  • Improvement: Grammatical corrections

Version 3.07 - General deployment
  • Feature: Added option to enable relaxDTMF

Version 3.06 - General deployment
  • Feature: Added fax detection options

Version 3.05 - General deployment
  • Corrected default value for Rx and Tx gain

Version 3.04 - General deployment
  • Corrected default value for "PRI dialplan"
  • Corrected default value for "PRI local dialplan"

Version 3.03 - General deployment
  • Allows more parameters in receive and transmit gains
  • Train Echo bug fixed
  • Added pri local dialplan
  • When changing the PRI Local dialplan, asterisk needs to be restarted!

Version 3.02 - General deployment
  • Allows more parameters in receive and transmit gains

Version 3.01 - General deployment
  • Allows for specification of first channel

Version 3.00 - General deployment

Version 2.10 - General deployment

Version 2.01 - General deployment

Version 2.00 - General deployment

Resource configuration interface

GUI unavailable.

Resource configuration parameters

ALERT! In the event you experience ISDN problems, please consult IsdnDebugging.

  • Description: free text field
  • PriNum: Select PRI1 for the first PRI, PRI2 for the second, ...
  • Signaling: select CPE if your PRI is connected a standard ISDN line of your ISDN service provider (phone operator), select NET if the PRI should behave like an operator ISDN line (for example when you interconnect your Escaux UCS system with another PBX system)
  • RxGain: receive gain, determines the amplification applied on the incoming signal. This can be used to raise or lower the incoming volume. You specify gain as a decimal number from -15% to +10%. Default value: 0
  • TxGain: transmit gain, determines the amplification applied on the outgoing signal. This can be used to raise or lower the outgoing volume. You specify gain as a decimal number from -15% to +10%. Default value: 0
  • Context: Context in which an incoming call on the PRI must enter. Typically, set to 'Incoming' (default value) in order to route incoming calls to the External Number Mapping context. Typically, set to 'NoRestrict' if you want to redirect the calls to any configured route as indicated in the route plan.
  • Overlap dialing: Whether the Escaux UCS can send outgoing calls using overlap digits. Default: no. If you need Direct Dial-in (DDI; in German "Durchwahl") you should change this to yes, then Asterisk will wait after the last digit it receives
  • Switch Type: signalling protocol family. Default value: Euro ISDN
  • PRI Dialplan: Sets an option required for some (rare) ISDN providers that require a dialplan parameter to be passed. This option is ignored by most PRI switches. It may be necessary on a few pieces of hardware. Valid options are: unknown, local, private, national, and international. This option can almost always be left unchanged from the default. Default: national.
  • Echo Canceller: Disable or enable echo cancellation (default is 'yes'). It is recommended that you do not turn this off. You may specify echocancel as 'yes' (128 taps), 'no' (0 taps, disabled), or a preset number of taps which are one of 16, 32, 64, 128, or 256. Each tap is one sample from the data stream, so on a T1 or E1 this will be 1/8000 of a second. Accordingly the number of taps equate to a 2ms, 4ms, 8ms, 16ms or 32ms tail length.
  • Use Echo Canceller for zaptel bridged calls: Enables or disables echo cancellation during a bridged TDM call. In principle, TDM bridged calls should not require echo cancellation, but often times audio performance is improved with this option enabled. Default: no.
  • Train Echo: In some cases, the echo canceller doesn't train quickly enough and there is echo at the beginning of the call which then quickly fades out. Enabling echo training will cause Asterisk to briefly mute the channel, send an impulse, and use the impulse response to pre-train the echo canceller so it can start out with a much closer idea of the actual echo.
  • E1/T1: Select E1 for Europe and T1 for the US
  • First Channel or channel range: Enter the first channel to be used by this interface. This value is only needed if not all zaptel interfaces are the same type, e.g. mixing E1 with T1 or FXS. For example if in the figure below PRI1 is used to connect a 24 port FXS channel bank, then PRI2 should start at channel 25. More information about how many channels each type or interface consumes can be found in the Zaptel-Asterisk-1.2x module documentation. Configuration examples can be found the AnalogInterface resource documentation. Since version 3.10 of the resource, you can specify a channel range. This range is specified in the following format: "first_channel-last_channel". Note that on E1 interfaces you cannot use channel 16 because it is a channel reserved for signalling. Thus, should you want to use channels 1-17 for 1 trunk (yielding 16 usable channels) you have to use a comma to separate this. The value would be "1-15,17-17". On T1 interfaces the signaling channel is 24, which also cannot be used.
  • PRI Local Dialplan: Sets the calling number's numbering plan. When this value has changed, a restart of asterisk is necessary to apply the new configuration.
    • unknown: Unknown
    • private: Private ISDN
    • local: Local ISDN
    • national: National ISDN
    • international: International ISDN
    • dynamic: Dynamically selects the appropriate dialplan
  • Fax detection: Fax detection enable to detect incoming and outgoing fax tone in order to deactivate the echo canceller when fax are detected. Normaly, you don't need to adapt this parameter as you can force to disable the echo canceller when the signal is bridged (cfr. supra). Possible value:
    • both: detects incoming and outgoing faxes
    • incoming: detects incoming faxes
    • outgoing: detects outgoing faxes
  • Resetinterval: Sets the time between restart of unused channels, defaults to 1 hour. Some operators and PBXs incorrectly interpret this as a restart of all channels. Should that be the case, set it to 'never'.


The use of Zaptel based cards requires the Zaptel-Asterisk-1.2x module.
Copyright © Escaux SA