Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!accuvax.nwu.edu!nucsrl!telecom-request From: Vance Shipley Newsgroups: comp.dcom.telecom Subject: Re: Recall / Flash Hook Message-ID: <5379@accuvax.nwu.edu> Date: 20 Mar 90 00:15:36 GMT Sender: news@accuvax.nwu.edu Reply-To: vances@xenitec.UUCP (Vance Shipley) Organization: SwitchView - Linton Technology Lines: 53 Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 10, Issue 186, Message 7 of 9 In article <5321@accuvax.nwu.edu> tadtec!tjfs@relay.eu.net (Tim Steele) writes: >To get the exchange back during a phone call, in the UK we use a 90ms >line break called Timed Break Recall (for those of us lucky enough to >have a modern exchange!). I gather you guys in the US use a 600ms >line break called Flash Hook or something. Is this right? Yes, you are quite correct. A "flash" (or "hookswitch flash") is widely accepted as a 600 millisecond on hook condition. Qouting from the EIA Standard RS-464 Private Branch Exchange (PBX) Switching Equipment for Voiceband Applications: 4 Technical Requirements 4.1 Central Office - PBX Trunk Interface 4.1.1 Supervision - Ground Start Trunks 4.1.1.6 Call Supervision 4.1.1.6.4 The PBX shall not generate momentary breaks in the dc path through the trunk circuit exceeding 100 ms on outgoing calls and for longer than ten seconds on incoming calls, except to signal disconnect or, on outgoing calls, to flash-recall a toll operator. If the PBX automatically generates flash signalling, it shall generate an on-hook indication of 300 ms to one second to signal a flash request. 4.8 Station Interface 4.8.3 Loop Supervision 4.8.3.5 Call Supervision 4.8.3.5.1 If flash signals (momentary on-hooks) from the remote terminal are used by the PBX to initiate internal calling features, the PBX shall ignore an on-hook signal of 150 ms or less; interpret an on-hook signal of 300 ms to one second as a valid flash; interpret an on-hook signal of 1.5 seconds or greater as a valid disconnect. 4.8.3.5.2 If flash timing is not provided, the PBX shall interpret an on-hook signal of 300 ms or greater as a valid disconnect. How's that for an answer? vance