Hello!
This time I present you with a case where eight-digit calling cumbers cannot be recognized for outgoing calls from the eSpace U1980 to PSTN, and how to troubleshoot it. Hope you find ot useful.
Symptom
In one office, two eSpace U1980s are deployed as the trunk gateway and voice gateway respectively. They are connected through a SIP trunk. The trunk gateway connects to PSTN through a PRI trunk.
In this office, prefix 0 indicates a local call; prefix 00 indicates a national toll call; prefix 000 indicates an international toll call. As usual, a called number is changed only once for all these outgoing prefixes. That is, when a called number matches an outgoing prefix, the system deletes the first digit (0) from the called number so that the peer PSTN can correctly recognize the called number sent from the eSpace U1980 trunk gateway to implement proper communication. In addition, no supplementary service such as automatic switchboard is configured in the office. Only simple voice services are implemented. An intra-office number (such as 6xxx1009) is registered with any IP phone under the voice gateway to make outgoing calls. No matter in local or toll calls (for example, a toll call to 00+158138926xx), intra-office number 6xxx1000 instead of the actual intra-office number 6xxx1009 is displayed to the called party.
Fault Location
In the configuration user view on the trunk gateway, run the show predeal and show prefix dn 0 /00/000 commands to view number change indexes and the association between outgoing prefixes and number change indexes. Outgoing prefixes 0, 00, and 000 are not associated with any calling number change indexes.
In the super user view on the trunk gateway, print logs. The procedure is as follows:
On the SecureCRT, choose File > Log Session to save Telnet session logs.
In the super user view on the trunk gateway, run the following commands to enable the log printing function:
debug debug os_pid_sip cmd 40
debug logtrace start pid sip&ccm&usam&siptk&pri tracetype all
d s p f on
Reproduce the fault. Dial 00+158138926xx on the IP phone whose number is 6xxx1009. Number 6xxx1000 is displayed as the calling number on the called party's mobile phone.
(Mandatory) On the trunk gateway, run the following commands to disable the log printing function:
d s p f off
debug logtrace stop
Open the saved session logs. It is found that the called number is changed. The first digit of the dialed number 00158138926xx is deleted, and number 0158138926xx is sent to the PSTN. In addition, based on analysis of the logs, 8-digit long number 6xxx1009 is sent to the PSTN as the calling number. Therefore, it is the carrier who changes all calling numbers to 6xxx1000.
Contact engineers of the carrier. It is learned that there is strict restrictions on the calling numbers sent to the PSTN. The calling numbers must be in the format of area code+8-digit calling number, that is, 10xxxxxxxx. If only an 8-digit long number is sent to the PSTN, the PSTN cannot recognize the number and changes the calling number to the charging number configured on the PSTN, which is 6xxx1000 for this office.
Solution
Based on the communication with engineers of the carrier, enable calling number change for outgoing prefixes 0, 00, and 000 so that 10 can be inserted into the start of each 8-digit calling number. Change the number attribute to national and the value of software parameter 257 (PRI trunk numbering plan) to 1 (ISDN telephone numbering plan) so that the PSTN can correctly recognize the actual calling number for an outgoing call.
When an intra-office IP phone user makes an outgoing call after the preceding changes, the calling number is correctly displayed to the called party.
Source: https://support.huawei.com/enterprise/en/doc/EDOC1000023012
That's all folks, hope you found my post useful, and don't forget to comment if you have further concerns or remarks.
Thank you very much!
