Path: csiph.com!weretis.net!feeder8.news.weretis.net!reader5.news.weretis.net!news.solani.org!.POSTED!not-for-mail From: Richmond Newsgroups: uk.telecom Subject: Re: Engaged tone Date: Sun, 19 Apr 2026 23:29:42 +0100 Organization: Frantic Message-ID: <82fr4q1t49.fsf@example.com> References: <10rkvi3$3vsri$2@dont-email.me> <82wly93f6d.fsf@example.com> <10s0sd8$31q5v$1@dont-email.me> <82cxzw9cp5.fsf@example.com> <10s257b$3qie5$1@dont-email.me> <82fr4rm6xh.fsf@example.com> <10s2vjj$36b8$1@dont-email.me> <82jyu21xfd.fsf@example.com> <10s3h74$3u5fm$1@dont-email.me> MIME-Version: 1.0 Content-Type: text/plain Injection-Info: solani.org; logging-data="625084"; mail-complaints-to="abuse@news.solani.org" User-Agent: Gnus/5.13 (Gnus v5.13) Cancel-Lock: sha1:n3RvfEQtjLX9FtvkpLrjJZWtti4= sha1:y8WG3Z33lUxQKPywpRxD8dWbfrY= X-User-ID: eJwNwYEBwCAIA7CXwJYyz0EZ/5+wJQG5blIhxsSs7bYQProHvwNt8qm2lyoqDezuWQZUZn762xAE Xref: csiph.com uk.telecom:39414 David Wade writes: > On 19/04/2026 21:56, Richmond wrote: >> David Woolley writes: >> >>> On 19/04/2026 14:11, Richmond wrote: >>>> ___ _ ___ _ >>>> >>> This is "equipment engaged", and is the tone equivalent of "all lines >>> to xxxx are busy, please try again later". Done correctly, one length >>> is louder than the other. >>> >>>> __ __ __ __ __ >>> This is "subscriber engaged", where the phone is ringing or off hook. >>> >>> "Number unobtainable", which is what you are looking for, is a >>> continuous tone, although normally replaced by a voice announcement. >> > > Aren't these SS7 call status tones > >> On my router there are two phone sockets and these have internal phone >> numbers **11 and **12 , so if I phone **11 from phone 1 I get a tone >> which is actually the equipment engaged tone above, but it must be >> coming from my router I guess because such a call need not go outside >> the router. Or maybe these tones are actually transmitted as error code >> and are then always translated into tones by the VOIP receiver or >> router? >> > well of course the call status is transmitted as a status code. The > tones are generated locally! If the call isn't set up so you haven't > selected a codec so you can't send a tone. Not sure if this is the > current protocol defs... > > https://datatracker.ietf.org/doc/html/rfc3261 > You say 'of course' as if it is obvious, but it isn't obvious to me. When I had an analogue line the tone would have been sent as a sound over the line in the same way as a voice. So how do I know that if I make a call to an analogue line the tone isn't created in the system somewhere and then sent as a sound (though digital) in the same way as voice?