in a previous message Priscilla Oppenheimer said:
>>Wouldn't robbed bit signalling be
>>implemented ONLY in customer-premise equipment?
>If you have a T1 tie line between your PBXs for example, the circuit really
>goes the Central Office for the phone company, of course. Doesn't their
>equipment have to know about the robbed-bit signalling in order to handle
>on-hook, off-hook, etc.? Just wondering. I'm a data person, not voice,
>(except voice over data over voice, i.e. VoIP and VoFR using data T1 lines
>that were originally designed for digital voice! ;-)
OK, I am a Voice & Data person (also known as a Smart A$$), so hopefully
I can clear some stuff up.
1. If this DS1/T1 terminates in a Central Office Voice Switch (5ess or
DMS100/250) then
some sort of signaling information must take place, for Voice Call
setup/Tear down
. One of three options:
-Robbed Bit signaling, the lest significant bit is robbed for A,B,C,D
signaling.
-Common channel signaling, the 24th channel provided rudimentary
signaling
-ISDN-PRI signaling, the 24th channel provides LAPD ISDN-User Part SS7
signaling
to the CO.
2. Most DS1/T1's that are used for Data will be Clear Channel. This means
that they
never terminate in a Voice switch. Instead a DACS(Digital Access Cross
connect
System), or Sonet Fiber mux, will pass the entire 1.544mbps stream
through
the CO out to the other end. It is then up to the "End" points to
provide signaling.
A Cisco router used HDLC, FRAME, etc, for "Signaling", even though to
the router
there is just one-long-stream of serial digital bits to work with.
P.S: We don't pass NNTP through the Firewall, so I have to reply via
email. Sorry this is so broken up.
-- Jeremiah Peace
-- Systems Engineer
-- Lucent Technologies
-- A+,MCSE,CCNA,LCTE VoIP,Definity G3
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