Intercom function on BT lines

June 14, 2006 2:23 AM

I'm sure there used to be a code one could dial on UK telephones which would cause the line to ring - thereby achieving intercom functionality? This number was something like *173, but either my memory fails me or it no longer works. Any ideas on the specifics?
posted by dance to technology (7 comments total)

Have a look at this list of network service codes. This Wikipedia article mentions the (prevention of) the use of ringback numbers as an intercom function.

From what I remember, it used to be *73, but it does seem to have changed.
posted by teleskiving at 2:41 AM on June 14, 2006

17070, then press 1.
posted by ed\26h at 4:20 AM on June 14, 2006

In some systems you do that by dialing your own phone number. Have you tried that?
posted by Steven C. Den Beste at 4:29 AM on June 14, 2006

I don't have a BT phone here, so I can't test it, but I remember it as *73 as well. That's the engineer test line, so the ring it gives is not the ordinary one.

There's also a delay before it works -- you'll get silence on the line for a while, then a voice telling you what number you are calling from. When it says "Start test", hangup then wait a while. The phone will ring. When you pickup, it'll ask you to dial next test. It's hard to talk over.

17070 also rings a bell (boom)
posted by bonaldi at 5:01 AM on June 14, 2006

@ Steven
So far as I am aware, dialling your own telephone number in the UK (on BT, Telewest, NTL) results in an engaged tone, but thanks.

@teleskiving
Thanks for the links, proved an interesting read. I wonder *why* they are so keen to prevent intercom use? Surely it makes no difference to them.

All: *73 seems no longer to work. Thanks!
posted by dance at 8:08 AM on June 14, 2006

What we used to do as kids was dial our own number then hang up before getting a busy signal and the phone would ring.

Lots of pranks started that way, AIR. Don't know if it would still work the same way.
posted by trinity8-director at 11:36 AM on June 14, 2006

We use it as an intercom sometimes as well, in New Zealand it's 137.
posted by The Monkey at 6:11 PM on June 14, 2006