[Asterisk-biz] E1 with SS7 signaling

[Race Vanderdecken]

www.footnotess7.com is now open to begin the creation of SS7 that can be
used with asterisk.

Sign up and list which and what parts you would like to work on.

Race V.

-----Original Message-----
From: asterisk-biz-bounces at lists.digium.com
[mailto:asterisk-biz-bounces at lists.digium.com] On Behalf Of Michael
Welter
Sent: Sunday, June 12, 2005 1:07 PM
To: c.savinovich at itntelecom.com; Commercial and Business-Oriented
Asterisk Discussion
Subject: Re: [Asterisk-biz] E1 with SS7 signaling

Christian Savinovich wrote:
> 
>  Francisco:
> 
>   Can you help me understand this :) ?.
> 
>   I am used to think one port with 24/30 channels, maybe one port
doing signaling (E1).   That's the way the Digium port will work.   How
does that differs from the SS7 port level, are they receiving the same
number of channels? Is it like channel 16 (on an E1) sends the messaging
to an out of band channel on the SS7 port, and if so, what channel is
that? if there are 30 channels on the digium port, will the SS7 port
handle 30 conversations?
> I keep thinking one Digium port to one SS7 port, since that's all I
need.  And finally, are all SS7 ports compatible?, or are there
"implementations"?, if so, how the heck am I going to know if what I am
paying for will work?
> 

As I understand it:

An E-1 circuit (2.048Kbps total) is divided into 32 64,000bps channels. 
  Channel 0 is reserved for framing and synchronization, and channel 16 
is reserved for signaling, leaving 30 channels for voice.  Channel 16 
_may_ be used for channel associated signaling (CAS) information.

Each E-1 from Hondutel will have 30 voice channels.  There is a V.35 
data connection, separate from the E-1 circuits, that carries SS7 
messaging between Hondutel and the customer.  All call setup and 
teardown (the signaling) for all the E-1 circuits is sent over this data

connection using SS7-defined messages.

This differs from a T-1 PRI circuit here in North America.  Each T-1 has

24 64,000bps channels.  The 24th channel (the "dchan") is reserved or 
signaling, leaving 23 voice channels.  The signaling takes the form of 
ISDN q.921 and q.931 messages using the HDLC protocol.  The signaling 
for each T-1 is carried in channel 24 of that circuit.

What I'm looking for is an adapter device that will allow me connect 
multiple Hondutel E-1 circuits, along with the V.35 signaling circuit, 
to one or more Asterisk systems.  An ideal configuration would be a 
device that connects to Hondutel E-1/SS7 circuits on one side and an 
Asterisk system using a DS3 interface (this assumes the Digium DS3000P 
card becomes available in the near future).  A practical configuration 
would be a device that connects with Hondutel E-1/SS7 circuits on one 
side and E-1/ISDN PRI circuits on the Asterisk side (converts the common

channel SS7 signaling to ISDN PRI signaling on each E-1 circuit). 
Another practical configuration would be a device that connects with 
Hondutel E-1/SS7 circuits on one side and SIP/RTP IP on the Asterisk
side.

I know there are Enterprise solutions, but the cost is in the $20-80K
range.

Thanks for your input.
_______________________________________________
Asterisk-Biz mailing list
Asterisk-Biz at lists.digium.com
http://lists.digium.com/mailman/listinfo/asterisk-biz