Line Config: Internal vs. External Number

[Andy Schmidt]

Hi,

The Lines | Manage screen has a column for:
- Identification
- Virtual Extension

Then, when you VIEW a line, you don't see these two fields any more. However, there ARE two input fields called:
- External Number
- Internal Number

It appears as if Identificaton=External Number and Virtual Extension=Internal number.

But that still doesn't tell me HOW these numbers are being used, how to choose the correct or most appropriate values for these number, how they are different from each other... what is the effect if I change one number, or the other? What do these numbers tie into (e.g., if I change a number, what other part of the system will I have to change to "match" that number).

I tried to find some "guidance" in the manual, but either I didn't look correctly or it isn't there. I also tried to search the forum, but it won't let me search for "external internal number lines".

 

[N_G]

We do give you a hard time dont we

The external number is just used for reference and display really. That is to say you can identify the lines easier if you enter the 'real' external number. You are right that we have to make the values consistent though in the next version.

The internal number is something like a virtual extension and is used internally to allow the gateway to register with the pbx... So should not be changed, or at least not without changing the gateway config. The external number is mainly for display and can be changed.

 

[Andy Schmidt]

Thanks Nick, for your time.

>> we have to make the values consistent though in the next version.<<

Yeah - really! I just realized there is yet another screen (the "Line Status") display, that uses totally different terminology for those same fields. Here the "External Number" is called "Line Number"? Basically none of these screen agree with what the content/label of these fields are!

As far as the config screens: I think it would be good to clarify the use of these two numbers (one is the "friendly name", display only, the other acts as an identifier within the PBX and thus should be a unique value) in the line config screens. It would also be good to include a practical example. Is a "line number" the "line #1", "line #2" as in the old PSTN days? Or is it supposed to be the "phone number", etc.

In any case, I had mine reversed (using the "real" phone number as the "internal" number and the 10801 as the "external".) I'll try to swap the two and see if things still work afterwards. Of course, if my system works with having defined the "internal" number as the lines' phone numbers, then you can't help but wonder if all these extra numbers are really necessary when they don't seem to have any functional impact either way...

Specially the PSTN lines can be confusing to set up, when the "Internal number" is 10801 and the "authentication ID" is 10801 and the "External number" is 10801... one can't help but wonder whether all that redundandy really serves to make things easier to set up - or whether you just end up giving your users a hard time by offering too many choices where you just end up typing the same info over and over.

The same is true for VOIP trunks - where the lines don't even HAVE a "phone number", but you set your own CallerID. Even inbound, it only answers to one inbound phone number (which can handle several parallel calls).

 

[N_G]

Actually its in the manual...

But in any case the fields are not redundant at all. Auth ID and Password are used for authentication. Internal number is an internal extension number - used by ALL gateways that i know of. External number serves for identification and is often the real PSTN number. The only one you could eliminate is the identification/external number but its very handy to know what phone line you are actually talking about.

This is all according to the SIP standard which has to cater for many devices and providers. I can assure you we are not in the business of adding fields just to piss off users. They are needed and unfortunately you will have to learn their use .....

 

[Andy Schmidt]

>> Actually its in the manual... <<

Darn - you are right!

I had read the entire manual back to back, but then not referred back to it when doing the work. I was following the "online help" (the little red/white inner tube):

 

[Andy Schmidt]

The external number is mainly for display and can be changed.

Well - would you know. I had followed your suggestion - and it took two weeks before it failed. I had swapped the external and internal numbers for the PSTN lines (AudioCodes MP-118), making the "external" numbers my "real" phone numbers, and making the "internal" numbers 10801...10804 - and it seemed to cause no ill effect when I did it.

However, after I had occasion to restart the the 3CX phone system service today, I suddenly was unable to make outgoing calls through these PSTN lines (incoming calls worked, registration status showed greed, and the MP 118 said that it was registered).

I then swapped the internal/external numbers again, making the INTERNAL my real phone number and the external 10801 - and it did NOT fix it. However, knowing that the problem only surfaced after a service restart, I restarted of the 3CX phone system service with my "original" settings and, voila, inbound and outbound calling started working again!

Sooo, I think I found out TWO things:

- the "external" number somehow seems to tie into some setting in the PSTN gateway (AudioCodes MP-118)
- changing the internal/external number apparently doesn't take full effect until AFTER the 3CX service restarts!

(No in my tests I did NOT touch the "authorization" sip userid and password).

 

[Andy Schmidt]

Hm,

3CX has 4 fields in the PSTN line configuration:

External Number: 10801
Authentication ID: 10801
Authentication Pwd: *****
Internal Number: 9349210
Outbound CAllerID: 10801

The ABOVE configuraiton worked.

When I change these settings, to follow your suggestion on how the use was intended:

External Number: 9349210
Authentication ID: 10801
Authentication Pwd: *****
Internal Number: 10801
Outbound CAllerID: 10801

Then the PSTN Gateway (from IP Address .130) registrations fail, but only AFTER I restart the 3CX phone system service (IP Address .136):

15:22:09.082|.\Authorization.cpp(323)|Log2||printDetailedInfo:[CM502001]: Source info: From: <sip:9349210@??.??.??.130>;tag=1c657279995; To: <sip:9349210@??.??.??.130><br>
15:22:09.394|.\Authorization.cpp(106)|Critical0|Authorization|AuthMgr::onAuthFailure:[CM102001]: Authentication failed for SipReq:  REGISTER ??.??.??.130 tid=ac657374216 cseq=REGISTER contact=9349210@??.??.??.136 / 6 from(wire); Reason: Credentials don't match, check that authorization-ID and password match the ones in extension settings<br>

So I'm baffled! I never touched the "Authentication ID" of 10801 and the matching password - so the credentials should match as before. From the testing and the above log message it almost seems as if 3CX is somehow matching the register "contact" against the "internal number" field - instead of using the Authentication ID?

Best Regards,
Andy