Getting Caller-ID with BT Inspiration or Pathway PABX

For years I’ve thought that caller-ID was broken on BT Inspiration switchboards (which are almost identical to BT Pathway, so this applies to both). More precisely, I assumed that BT’s Caller-ID signal was either not working on my POTS lines, or was not of a standard compatible with the Inspiration. It wouldn’t be the first one – note the nonsense with the default “Guarded Clear” mode, which isn’t actually implemented on any BT lines I’ve ever come across.

CLI on ISDN worked fine, incidentally. It was just an irritation that it didn’t on the POTS lines.

Well, it turns out that it does work just fine, except it’s called CDR, and for some reason, it’s not enabled by default! Technically, they’re right not to call it CLI, which technically, is the standard used on ISDN. However, in the real world the term is applied to caller ID on analogue lines too. As a user of the telephone, why should you care about such technicalities? But you do, and you will have to enable it separately, as CDR, for any lines you want it to work on. IN the menus go to  System Programming/Lines/PSTN Programming/CDS Detection and turn it on. After which it just works.

In other places the terms Caller-ID and CLI are used interchangeably (for example, the CLI History refers doesn’t care whether it was ISDN/CLI or POTS/CDS). Don’t let common sense put you off.

Do also make sure that Caller-ID is enabled on the line – from BT dial *234#. Sometimes this is a “paid for” service, and has to be enabled. If you ask them nicely, because you’re being plagued by nuisance calls, they’ll enable it for free. I think it’s free if you renew your contract for 12 months too, but I have caught them starting off  at no charge and then billing you for it later. Watch out.


Leave a Reply

Your email address will not be published. Required fields are marked *