[Asterisk-Dev] Question about E1 Card / ISDN PRI
vinod at netyantra.com
Thu Mar 27 22:25:54 MST 2003
On Sat, Mar 22, 2003 at 09:12:20AM +0800, Leo Ann Boon wrote:
- Some answers:
- 1. ISDN PRI is usually from your telco to you. It's normally used to
- replace analog lines. 1 E1 PRI is equivalent to 30 analog lines, so you
- can imagine the savings in wiring. But, you can't directly plug a phone
- to an E1 PRI, it has to be splitted up using a PBX (like the *).
- 2. You'll have to use CCS (Common Channel Signaling) or more commonly
- known as D-Channel signaling. Excerpts from my zaptel.conf for an E100P:
- The dchan is a must for PRI, it tells the E100P to use channel 16 for
- signaling instead of voice. The crc4 option is usually required for E1
- PRI, but if check with your telco. I've seen some E1 PRIs supplied
- without crc4 (no thanks to DMS100).
- 3. I don't think S/T or U applies to PRI, it's for BRI. Perhaps someone
- else can explain this better.
- 4. R2MF is an E1 CAS (Channel Associated Signaling), it's like T1
- robbed-bit signaling. PRI is CCS. IIRC, the zaptel supports R2
- signaling for China.
- Help this helps.
- Vinod Sankar wrote:
- >I have a few basic questions. Apologies in advance if this is
- >the wrong forum for what should be a Digium FAQ.
- >I'm trying to use the Digium E1 card to provide an IP PBX like
- >application to an enterprise that needs about 30 telephone lines,
- >in India. India supports R2MF and ISDN PRI (Euro ISDN) signaling
- >standards. The Digium card supports only ISDN PRI.
- >The questions are,
- > - Are ISDN PRI lines used only for branch to branch
- >(closed group) calling, where the PSTN is unaware of how the
- >channels are used (Voice/Data) or can PSTN switches terminate
- >voice calls from public analog phones into this ISDN PRI circuit ?
- > - The Zaptel configuration mentions framing options for defining
- >spans for E1 lines as either CCS or CAS. Do I specify CCS for an
- >E1 ISDN PRI line from PSTN terminating on this card ?
- > - What interface does Digium E1 card support S/T or U ?
- >Also, quickly, what is the difference between R2MF and ISDN PRI ?
- >If someone could point me to a website that has more info on these
- >subjects, that would be great.
- >Vinod Sankar
- >Asterisk-Dev mailing list
- >Asterisk-Dev at lists.digium.com
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- Asterisk-Dev at lists.digium.com
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