This page describes the PRI Channel and contains instructions on how to add one to the VoipNow system.
VoipNow automatically determines the available (i.e. unassigned) physical PRI channels installed on the server. If no PRI channels are available, the Add PRI Channel icon is greyed out and unavailable. On mouse over, an explanation gets displayed.
The Primary Rate Interface channel is a type of ISDN designed for larger companies, typically used to connect a PBX to a telephone exchange.
- It includes 30 B-Channels (23 in USA) and one D-Channel.
- It is usually transmitted through E1 lines (T-1 lines in USA).
To set up a PRI Channel, first go to the System menu on the left and click on Channels. In the Channel Management page, click the Add PRI Channel icon under the Trunks area.
Enter channel details
- Clone settings from channel: Replicates all the settings of an existing channel.
- Name: Requires a descriptive name used to identify the channel.
- Use channels From ID <number> To ID <number>: Select the channels that belong to the previously selected node you want to group. The lists display only the channels that were not used in other configurations. You can add/remove several channel intervals using the +/- icons.
- Group ID: Select the ID of the channels group previously defined.
- Channel capabilities: Select the channel functionality: Incoming – Only incoming calls can be received through the channel. Outgoing – Only outgoing calls can be sent to the channel. Both – The channel can both receive and send calls.
- Charging plan: Specify the channel type. Paid – The channel charges a fee every time it is used. Free - The channel can be used for free to call any destination.
- Default language: The channel will have a default language code that determines the language of the sound files played on this channel. The default language is English. Select your language using the drop-down list.
- Channel notes: Add any channel details you want.
Define signaling and voice quality options
Choose the signaling method used on the channel. Default method: fxo_ls.
If set to Yes, VoipNow will apply an echo cancellation algorithm to the voice transmitted over this channel.
Echo cancellation when bridged
If set to Yes, VoipNow will apply an echo cancellation during pure TDM bridging.
Enable echo training
Trains the echo canceling algorithm.
Relax DTMF detection
Useful if you are having problems with the DTMF tones detection.
Set a receive gain using the drop-down list.
Set a transmit gain using a drop-down list.
Answer the channel immediately
Specify if the channel should be answered to immediately or the simple switch should provide dial tone, read digits, etc.
Tones are played on the channel for
Specify for how long the generated tones (DTMF and MF) will be played on the channel.
Distinctive ringing on FXO lines
Indicate if an attempt at recognizing distinctive ring styles on incoming calls should be made or not.
If the phone device connected to this channel has ADSI (Analog Display Services Interface) capabilities, set Enable ADSI to Yes.
Enable busy detection
If set to Yes, the incoming audio signals during a call or a dial attempt will be analyzed in order to recognize busy signals.
How many busy tones to wait before hangup
Specifies how many busy tones the system waits for before hanging up.
Busy tone cadence
Allows you to specify the pattern of the busy signal.
Use polarity reversal to mark answered remote calls
Specifies whether the system must check for a polarity reversal to know when an outgoing call is answered by the remote party.
Hangup on polarity reversal
Specifies whether a polarity reversal is used to signal the disconnection of a phone line.
Detect call progress
If set to
Call progress zones
Defines the timing and frequencies for call progress detection.
Specify how long the system should take before considering to hung up on a non-ringing line.
For FXO (FXS signaled) devices, this setting specifies whether to use pulse dial instead of
Specifies whether the system will try to detect incoming, outgoing, both types of faxes or it will not detect faxes at all.
Specify the length of the jitter buffer.
Choose CallerID preferences
Use CallerID name
Specify the CallerID name that will be sent for all outgoing calls routed through this channel.
Use CallerID number
Specify the CallerID number that will be sent for all outgoing calls routed through this channel.
In the case of phones, if set to
Select the CallerID signaling method using the drop-down list.
What signals the start of callerID
Specify the type of signal that marks the start of the CallerID.
In the case of FXS phones, if set to
If set to Yes, the system will activate the call waiting function for all calls routed through the channel.
Restrict callerID presentation
If set to
Use callerID presentation
If set to
Send callerID after [X] rings
Some countries (e.g. UK) have ringtones with different ring patterns.
CallerID on call waiting
Specifies whether Asterisk will send CallerID data to the handset during call waiting indication or not.
Set the channel functions
Set the channel functions in the Channel Features section.
- Transfer to busy extensions: If set to Yes, the system performs flash-hook transfers even if the destination channel is busy. If set to No and the destination channel is busy, the system returns the call to the user that performed the transfer.
Flash-hook transfers are used in the call waiting feature. If a new call rings while the called party is involved in a conversation, Instead of producing a busy signal, the new caller hears the ringing sound and the called party hears a special beep tone. If he chooses so, the called party can depress send a flash-hook by briefly pushing the phone's hookswitch. The original caller is put on hold, and the new caller is connected. Repeated flash-hooks will swap between the two callers. On a PBX, a flash-hook will produce a new dial-tone, allowing a three-way conference or call transfer.
- Support three-way calling: If set to Yes, the channel supports conferences made up of three participants.
- Support flash-hook call transfer: If set to Yes, the channel supports call transferring by performing a flash-hook and then dialing the transfer destination's number.
- Support call forward: If set to Yes, the channel supports call forwarding features.
- Support call parking: If set to Yes, the channel supports call parking/unparking features.
Customize channel preferences
|Switch type||Choose the PRI switch type your PRI line is connected to. The default type is National. The other available values are dms100, 4ess, 5ess, EuroISDN, ni1, qsig.|
|Network specific facility||Some PRI switches (AT&T for example) require that you provide the network specific facility. The default value is none. Other values possible include sdn, megacom, accunet.|
|PRI dial plan (Rarely used!)|
Rarely used. Controls the Type of Number (TON) and the Numbering Plan Index (NPI) associated with the called party information element. The values available are:
Default value is National. This is the recipient of the call. This parameter is required only by a few types of PRI switches. If your switch does not require this parameter, it will simply be ignored.
|PRI local dial plan (Rarely used!)|
Rarely used. Controls the Type of Number (TON) and the Numbering Plan Index (NPI) associated with the calling party information element. The available values are:
Default value is National.
|PRI callerID international prefix||Specifies the international prefix part of the dialed number. The default value is 00. Another example of a valid international prefix is +.|
|PRI callerID national prefix||Specifies the national prefix part of the dialed number. The default value is 0. Another example of a valid national prefix is +49.|
|PRI callerID local prefix||Specifies the local prefix part of the dialed number. This text box can be empty. Examples of valid local prefixes: 0711 or +49711.|
|PRI callerID private prefix||Specifies the private prefix part of the dialed number. This text box can be empty. Examples of valid private prefixes: 07115678 or +497115678.|
|PRI callerID unknown prefix||This text box can be empty.|
|PRI reset interval||Specifies the time interval between resetting unused channels. |
Default value is 3,600 s. Some PBXes have problems with channel resetting. In these cases, you can set the time interval to a larger value (e.g. 86,400 s).
|Send overlap digits||Specifies whether a dialed phone number's digits should be sent to the switch by using the overlap sending procedure or the en-bloc procedure. If set to Yes, overlap sending will be used. |
Default value is Yes. The overlap sending procedure means that the system sends each dialed digit in its own ISDN information message. The en-bloc procedure means that all digits are sent in the same ISDN setup message.
|PRI indications||Specifies the type of signaling used for indicating events such as busy and congestion. When the setting is In band, the system signals busy or congestion using in-band tones and does not answer. When the setting is Out of band, the system disconnects with busy or congestion information code and the switch will play the indication tones to the caller.|
|Force all PRI channels to be marked exclusively selected||If set to Yes, the system will override the existing channels selection routine. As a result, all PRI channels will be marked as exclusively selected.|
Set ISDN parameters
- Transmit facility-based ISDN: If set to
Yes, the transmission of facility-based ISDN supplementary services is enabled.
- Set ISDN timer t<numeric_value_1> to <numeric_value_2> ms: Set ISDN timers. <numeric_value_1> and <numeric_value_2> accept values between 1 and 99,999. You can create several ISDN timers. Use the + and - buttons to add more text boxes.
Set timing parameters
Set the timing paramters used for non-PRI T1 lines. All text boxes accept numeric values that range between 1 and 9999ms:
- Pre-wink time
- Pre-flash time
- Wink time
- Flash time
- Start time
- Receiver wink time
- Receiver flash time
- De-bounce timing
Assign channel to channel groups
Assign the channel to one or several channel groups in the Channel Group section:
- All groups: Lists all the groups currently in the system. To assign the channel to a specific group, click the desired channel and it will be automatically moved into the Assigned groups pool.
- Assigned groups: Lists the groups the channel is assigned to. To remove the channel from a group, click the desired channel and it will be automatically moved back into the All groups pool.
Configure public phone numbers and DIDs
Configure the public phone numbers and DIDs as sent by the channel provider. Select the Set up the public phone numbers assigned to the channel checkbox. If you want to add the new channel without configuring the public phone numbers, deselect the Set up the public phone numbers assigned to the channel checkbox and click OK. For more info on how to add public phone numbers, check the Manage Public Numbers section.
Set channel costs
Set up the channel costs charged by the channel provider, based on the call destination. Select the Setup channel costs checkbox. You won't be able to do this unless you have defined a Paid charging plan in the Channel setup page. For more info on how to add channel costs, check the s section.
Click OK to add the new channel. If you want to add the new channel without configuring its costs, deselect the Setup channel costs checkbox and click OK to save the channel costs.
Except where otherwise noted, content in this space is licensed under a Creative Commons Attribution 4.0 International.