I am interested in finding out the extent to which 4b3t line code is
still in use. It is my understanding that 4b3t was used extensively
during the initial ISDN rollout in Germany, but that it is now being
replaced by 2b1q lines.
My questions are:
- which countries still use 4b3t?
- are u-interface echo cancellation chips for 4b3t still available?
- approximately how many 4b3t lines are in existence in Europe? Are
they being actively replaced with 2b1q? If so at what rate?
- are there any companies (Seimens?) that still support 4b3t
Thanks in advance for any input. My company makes a protocol analyzer
that works on 2b1q lines, and we are considering adding 4b3t
capability. Obviously, we are trying to determine to what extent such
a product would be useful in Europe.
Applied Signal Technology