R2 MFC signalling through E1 framing 2

[john00436]

Hi Gurus,

I want to know about the R2 MFC signalling for E1 connection. I have few doubts,

Which codec and companding methode is used for PCM coding (G.711 A-law or u-law)? I learned from some where that E1 uses A-Law companding. Is that right?

Whether the time slots for the voice channels are fixed or are they allocated dynamically?

 

[biglebowski]

You're best of googling CAS or R2.

R2 is CAS (channel associated siganlling) basically it's an E1 with a total of 32 channels of which 31 are bearer/voice and 1 is framing. It is sometimes called a 31 channel bearer or 31 channel signalling and i've mainly seen it used for dealerboard systems or trunk ties.

It's quite old now and only really used for specialist applications

When I was born I was so suprised I didn't talk for 18 months

 

[ISDNman]

Generally speaking A Law is used with E1 and mU law with T1, but I am pretty sure there are exceptions.

R2 is a signaling protocol so it covers signaling only, not the voice parameters.

The one time I ran across this we bought a box to convert the R2 to ISDN PRI. I can't recall the company that made the box, but if you wan't I'll look it up.

The country was in the middle east and they did not have PRI there.

If you ask a better question you will get a better reply. Be specific so we can help!

 

[biglebowski]

A law is used in europe and mu law in the US. You can get a law or mu law E1 and doesn't really matter as long as both ends are configured the same.

When I was born I was so suprised I didn't talk for 18 months

 

[john00436]

In case of ISDN PRI around Multiple Subscriber Numbers (MSN)are possible. I just want to know whether something like that is possible in case of R2 also?

Yeh thank you biglebowski. I know its Channel associated signalling. if its like that, (i mean inband) is MSN really possible?

 

[biglebowski]

No it's not possible on CAS.

I don't know if that answer was supposed to be sarcastic but why didn't you just ask that question in the first place.

When I was born I was so suprised I didn't talk for 18 months

 

[john00436]

Thank you biglebowski.

I just wanted to know whether the Subscriber numbers allocated by the Telco is same as the voice channnels available in the E1. ie. 30 channels. And whether one number is fixed for one channel? Or the channel allocaion is done dynamically?

Thanks in advance
John

 

[biglebowski]

Channel allocation varies it can be cyclic or linear but is set on the switch by the supplier. If its an in/out trunk it's generally linear channel selection using HILO (highest in lowest out) CAS supports DDI so you could have 1000 numbers on a 31 channel trunk.

When I was born I was so suprised I didn't talk for 18 months