Hello George,
Great reply.
>The AMI T1 signal has a spectrum peak at 772 kHz and therefore occupies considerably more bandwidth than you suggest, depending on how you define bandwidth<
Where do spectrum peaks occur for 6 Mbps ADSL and 51 Mbps VDSL?
Your descriptions of the rationales and formulas used to space repeaters were useful to me. I always thought that the span parameters were rather constant, but you've shown me otherwise.
>It was customary to segregate T1 signals in separate binder groups, I think, to reduce crosstalk into voice pairs but I'm not sure that was the primary reason.<
They also used to use screened cable for T1, if I'm not mistaken.
>Single pair drop wire that I am familiar with is not twisted but, as it is single pair, there is no crosstalk issue. Multi-pair drop cables, called service wire, I think, use twisted pairs.<
I would think that untwisted drop cable would not be a problem for NEXT/FEXT, unless multiple lines were brought onto the premises in that fashion. I would be more concerned about high frequency ingress, due to un-twisted pair cable's lower noise immunity. Would you agree?
Other things that I'm curious about are the effects of multiple splice points on sub pairs and the possible ensuing reflections that might occur at some point, and the need for sealing current on the older pairs. I've expressed these issues here in the past but would like to hear how you would respond to them. Do you think that a maximum number of splice points should be specified, and what about sealing current?
Frank |
