Carlos E. R. wrote:
On Saturday, 2009-07-18 at 20:42 +0200, Per Jessen wrote:
Fiber?? Where does fiber come into the picture? Nobody's mentioned that sofar. I guess you assumed "digital" = "fiber", but that's definitely not correct.
I have no idea what a telco might feed a fiber with - it'c clearly all digital, but what kind of phones do you use with it and do you hook them up? Around here we have only analog or ISDN phones, and both can easily be used with the digital signal coming over the ISDN line.
A bunch of T1 or E1, actually PRIs, to a big PBX. Not exactly ISDN, but internal "subscribers" can see an ISDN. In theory, I've never seen it, personally.
I have often done that. I've set up TDM statistical muxes, where there'd be one or more T1s (actually PRI ISDN) or a T3. The incoming DS0s (64 Kb/s channels) can be sent to a wide variety of connections or devices, depending on needs. There are two flavours of ISDN, basic rate, which is 2 x 64 Kb/s B channels + 1 x 16 Kb/s data or primary rate, which is (in North America) 23 64 Kb/s B channels and one 64 Kb/s D channel. The B or bearer channels are what carries your data, phone calls etc., and the D channel is used for signaling, status etc. A business with a PBX will often get 1 or more primary ISDN connections. You use a basic rate ISDN for data up to 128 Kb/s, which can all be used for one connection or split for two simultaneous 64 Kb/s connections. A standard voice call will use one 64 Kb/s channel. I have often used the basic rate ISDN to set up a PBX extender, which, with G.729 voice compression, can squeeze 10 calls into 128 Kb/s. This is used to extend a PBX to phones at another location. The connection between sites can also be IP. I've used IP over fibre to connect a pair of these extenders. I've also used ADSL lines. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org