Outbound PRI calls fail with error code 90

Owned by Nathaniel Halbrooks
Last updated: Oct 14, 2024 by Kelli Higdon
3 min read

When setting up a PRI circuit to work with Switchvox using a Digium T1/E1 interface card you may encounter a common issue where incoming calls are successful but outbound calls fail, with Switchvox playing back an error message saying that the call has failed with "Error Code 90".  There are two issues which will cause this scenario and they are fairly easy to remedy, and are listed below along with the steps to remedy them.

 

Issue 1:  Incorrect Caller ID Settings.

If you are unable to send outbound calls and you have not set your "Number to display in caller ID" field in you PRI's B Channel - Channel Group or if you have set this to a number other than the main DID for your PRI circuit, the Telco may be rejecting the outgoing call.  You may also have this value set, but have a "Caller ID Rule" setup under "Setup > Outgoing Calls" that modifies the Caller ID name and number when sending certain (or all) outgoing calls.  

To remedy this issue follow the steps below:

  1. Set the "Number to display in caller ID" field to the main phone number DID of the PRI line by modifying the Channel Group containing you PRI's B Channels by going to "Setup > Channel Groups" in the Switchvox Admin Interface. 

  2. Then check the "Caller ID Rules" tab under "Setup > Outgoing Calls" and make sure you are not overwriting the caller ID number with a Caller ID rule entry.  

  3. If this does not resolve the issue, check for the "PRI/BRI Dialplan" issue in "Issue 2" below and make sure if you are not receiving the "Invalid number format" cause code in the PRI Debug. 

  4. Call your Telco's support line and have them analyze an attempted outbound call, they may be expecting a different caller ID number than what you are sending and should be able to advise you or allow the number you are sending as long as that DID (phone number) is associated with your account.

 

Issue 2: PRI/BRI Dialplan and Local Dialplan settings. 

The PRI DialPlan and PRI Local DialPlan types are set incorrectly:  This issue is fairly easy to identify and correct, first grab a PRI Debug log by going to the Switchvox Admin interface then to "Server > Advanced Debugging" and start a PRI Debug session, then attempt to send and outbound call and then stop, download and analyze the packet capture.   You should see the Switchvox system send a SETUP message, if the PRI DialPlan and/or Local DialPlan type is set incorrectly, you will see the PRI switch respond to the setup message with a RELEASE COMPLETE message containing the follow error cause:

< Time: 1352062561.783502

< Protocol Discriminator: Q.931 (8)  len=9

< Call Ref: len= 2 (reference 6/0x6) (Terminator)

< Message type: RELEASE COMPLETE (90)

< [08 02 80 9c]

< Cause (len= 4) [ Ext: 1  Coding: CCITT (ITU) standard (0)  Spare: 0  Location: User (0)

<                  Ext: 1  Cause: Invalid number format (28), class = Normal Event (1) ]

 

To correct this condition follow the steps below:

  1. Modify the PRI/BRI DialPlan and PRI/BRI Local DialPlan settings under the Channel Group settings for the PRI's "B Channels" group, note that saving these changes will restart the phone system (not reboot the server) which will cause any calls to drop and allow no new ones for up to a couple of minutes.  Go to "Setup > Channel Groups" in the Switchvox Admin interface and modify the Channel Group that contains the PRI's B Channels.

  2. Change the PRI/BRI Dialplan and PRI/BRI Local Dialplan settings to "Unknown" (if already set to "Uknown", try "National ISDN") then save the Channel Group.  

  3. Try placing another outbound call, try setting it to each of the other settings until you can get outbound calls to send.  

  4. If none of these settings work, set the PRI/BRI DIalplan and Local Dialplan settings back to "Unknown" and contact your Telco's technical support.

 

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