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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

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?

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...

Hi, Thanks to all for sharing their valuable knowledge & time.... Regds. John

Hi jerryreeve, I think we are both saying the same thing in different ways. My objective is mere "basic understanding"..... thankss.... Regds. John

Hi ISDNman, I simply couldn't imagine 2 waves with the same frequency range to co-exist in a single loop without interfering.... That was the original quest.... AM was my own assumption, very sorrry..... Regds. John

Hi SYQUEST, It basicly applies to toll transmission lines (probably an old technique) were multiple voice channels are amplitude modulated & are multiplexed using FDM. Ref. "Understanding Telephone Electronics Fourth Edition.pdf" pg. 32.... Link...

Hi jerryreeve, Thanks.... Plz. refer to this link: http://www.epanorama.net/circuits/teleinterface.html "full operational amplifier based hybrid circuit diagram" Looks like the same thing is happening either way.... Regds. John

Thanks all of you for your help & support: I now have a decent idea of what a Hybrid exactly does.... Tx1 |--->---| Rx2 | | Rx1 |---<---| Tx2 Loop Current: Tx1 + Tx2 Rx1 hears: (Tx1 + Tx2) - Tx1 => Tx2 Rx2 hears: (Tx1 + Tx2) - Tx2 => Tx1 I hope...

What does the Hybrid ckt. exactly do to carry "both the Tx & Rx frequencies co-exist on a single pair of copper" Is it this: Tx signal is: A.Sin(wt) Rx Signal is: B.Sin(wt) Hybrid 4 to 2 does: A.Sin(wt) + B.Sin(wt) on Tip A.Sin(wt) - B.Sin(wt) on Ring Hybrid 2 to 4 does...

Thanks for the replies...... 1) What I am not able to digest is how can frequencies in the order of "180 Hz to 3.2 kHz" travel such long distances (CO to CPE) without any modulation, well DC loop current & differential signaling could help. 2) Plz. refer to the link below...

Hi Gurus, I have been surfing for some time but am not able to figure out as to which modulation technique is used for voice communication over the two wire i/f from CO (Tip & Ring). There are places were I find Amplitude Modulation is being used with distinct carriers for Tx & Rx, is it true...