Kris, the reason we don't put T-1 on cable pairs is of course NEXT & FEXT. The receive level from a T-1 MUX is 6 Volts P:P so it will spill all over the cable. The standard for T-1 in seperately shielded pairs. We do use twisted pairs at a cross connect panel for short runs... (DSX-1 Panel)
The HDSL technology does allow for T-1 on cable pairs but it uses 2B1Q protocol and there is really only 12 channels of the T-1 signal on each pair. 2B1Q was developed by Northern Telecom in Ottawa. 73 John VE3AMZ Retired, Bell Canada and MTS Allstream ----- Original Message ----- From: "Kris Kirby" <[email protected]> To: <[email protected]> Sent: Sunday, February 28, 2010 11:20 AM Subject: Re: [Repeater-Builder] Re: LOOONG audio runs > On Sat, 27 Feb 2010, JOHN MACKEY wrote: >> Using balanced audio in a broadcast environment, I have on rare >> occasions experienced issues with cross-talk between long runs of >> un-shielded balanced audio lines. (inductive pickup??) I always >> wondered if the wires were truly balanced when that happened. > > That's probably NEXT or FEXT, which is near-end cross-talk and far-end. > Bell documented this stuff somewhere; I've read the book. There's a > reason why they don't run the T1 lines with the voice lines or why they > don't stuff the entire binder full of T1s. > > Of course, that same book explained how to use the cable pairs as > resistors to heat up the cable, which has been done a few times in NYC, > resulting in dead pairs in the cable due to too much power/heating on a > given pair. > > -- > Kris Kirby, KE4AHR > Disinformation Analyst > > > ------------------------------------ > > > > Yahoo! Groups Links > > >
