Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!pacbell.com!lll-winken!telecom-request From: D.Heale@ee.surrey.ac.uk Newsgroups: comp.dcom.telecom Subject: Re: Collect and Third-Party Billing Message-ID: Date: 13 May 91 16:35:05 GMT Sender: Telecom@eecs.nwu.edu Organization: TELECOM Digest Lines: 16 Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 357, Message 5 of 10 The system used in the UK to prevent collect calls to payphones is that they send alternating tones for a few seconds when answered which the operator will recognise and presumably treat as though the call had been refused, these tones are also sent to the operator when called from a payphone to prevent services not billed by metering pulses being used. Presumably if a PABX or answering machine sent the same tones it would also stop collect calls. I have come across one PABX system where this would have been useful as some DID extensions were redirected to the main switchboard to prevent collect calls being accepted. However when the switchboard was closed at night a recorded message was given advising callers to ring the DID number for the appropriate extention even if that is what had been dialed.