Date: Tue, 4 Jan 2000 00:55:29 +0000 (GMT) From: Andrew Gordon <arg@arg1.demon.co.uk> To: Leif Neland <leif@neland.dk> Cc: freebsd-isdn@freebsd.org Subject: Re: isdn-"hubs" and isdn-"switches" Message-ID: <Pine.BSF.4.21.0001040040020.20496-100000@server.arg.sj.co.uk> In-Reply-To: <008a01bf5638$515bef00$0e00a8c0@neland.dk>
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On Mon, 3 Jan 2000, Leif Neland wrote: > According to specs, the S-bus should be a single line, terminated in > either end, and the terminals should preferably be located also near > the end; taps along the way are not recommended, and Y-splits > definitely not. I don't know where you got this from. The normal "rules" are up to 150m total length, with up to 8 taps along the way, with a maximum tap length of 1m, or alternatively up to 800m with no taps. > The topology of my house makes it difficult to follow these rules, if > I want phones in differerent rooms.. Unless you have a very large house, you should be able to make things fit. Note that these "rules" - like all cabling rules - are designed to simplify the problem, so that any installation obeying the rules is guaranteed to work. In reality, there is a trade-off between the total length, number of taps/T-junctions, length of taps, accuracy of termination etc. Many combinations not permitted by the rules will also work, though it is hard to guarantee this in advance. > > Therefore I could use an "isdn-hub". Does such a beast exist? I have never seen one. It would be nearly as hard to make one as it would be to build a simple PBX, and the PBX would be much more useful, so I suspect noone has bothered. > > Or should I rather get a PABC? This depends what you want to do, and how much you pay for the equipment. In the UK, ISDN phones are hard to find, and PBX with additional S-bus ports are much more expensive than ones with just analogue telephone ports. Hence the best combination for me is an analogue PBX for phones, wired in parallel on the S-bus with the PCs running i4b. You can still configure the system, for example, so that an analogue phone rings (via the PBX) on a particular MSN number, but the i4b answerphone answers it if you have not picked up the phone after a while. If ISDN phones are cheaper where you are, the best option may be different. > Can i4b work as a PABC, i.e. can I put more isdn-adapters in, and > connect a phone to each isdn-adapter? No, the S-bus is not symmetric: connecting an ISDN phone to an adapter in a PC would fundamentally not work at the hardware level, never mind the software issues. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isdn" in the body of the message
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