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anybody can help me clarify the concept?

Viewing 3 posts - 1 through 3 (of 3 total)
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  • 18th April 2005 at 22:55 #29379
    sojid
    Guest

    1. PRI Signaling Protocols: National ISDN-2, Euro ISDN NET5,
    2. T1 CAS
    3. E1 CAS

    what is the different of them? thanks

    19th April 2005 at 19:31 #29380
    MikeM
    Guest

    Sojid,

    These are basic signaling standards for T1/E1. There are really 2 basic types. ISDN (such as PRI signaling) and CAS. ISDN signaling uses one of the channels on the T1 or E1 to signal call setup/tear-down messages along with other information like ANI, etc. So with a T1 (normally 24 channels), channel 24 is used for this signaling information. This channel is called the D-channel. On an E1 channel 16 is used as the D-channel. The remaining channels are then used for the actual voice. The benefit of ISDN is the connection time is very fast and carriers can offer many services on top of ISDN.

    CAS (Channel Associated Signaling) is when a portiion of each channel of a T1 or E1 is used to signal the call connection/teardown so instead of 64kb available for voice you really only have 56kb. This generally does not cause a problem with voice communications. The main down side to CAS is that it is much slower than ISDN.

    If you need more in-depth information, I suggest you research ISDN and CAS on the web.

    Mike

    25th April 2005 at 11:37 #29381
    sojid
    Guest

    Dear MikeM,
    “ISDN signaling uses one of the channels on the T1 or E1 to signal call setup/tear-down messages along with other information like ANI, etc”

    is that means i only need to apply for ISDN-PRI for my gateway from the carrier? for example, i ask the carrier to provide 10 ISDN-PRI if i need 10 E1? is it correct concept?
    thaks again

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