- This topic has 5 replies, 1 voice, and was last updated 12 years, 7 months ago by pix.
1st September 2008 at 10:11 #53754RamGuest
How a signaling link can be known to operate as full-duplex. We define a single time slot and how it can work in full duplex mode. Pls clarify1st September 2008 at 14:06 #53755pixGuest
one timeslot = 1 timeslot in UL (using lower frequency band) + 1 TS in DL (using upper frequency band)
when you say frequency ARFCN “1” is allocated to one TRX, actually it means that the TRX will transmit in a DL frequency 935.2 MHz and receive on a UL frequency 890.2 MHz .
that’s why it’s full duplex.
that’s the same for Abis links : one TS actually describes 2 TS in opposite directions.1st September 2008 at 18:21 #53756RamGuest
Thanks for the reply. I am concerned with the ss7 signaling link. we define one time slot per link between the nodes. How that one TS can act in full-duplex mode. Pls clarify1st September 2008 at 18:35 #53757pixGuest
i just clarified !!
what you call one timeslot is implicitely equivalent to 1 timeslot in DL and 1 timeslot in UL.
this is physical.. just ready wikipedia about E1 for instance… you have 2 pairs of cables in one E1 : 1 pair for UL and 1 parir for DL.2nd September 2008 at 07:23 #53758RamGuest
I am clear now with duplex communication. I also need to know the technique by which two exchanges interact with each other. For example, we speak that the 64kbps speech is carried by a device in E1. How it is carried. In electricity, the current will flow from higher potential to lower potential. Is there any similar technology in speech transfer also. I dont want to restrict it to speech. I want to be cleared with signaling link also.
ram2nd September 2008 at 08:26 #53759pixGuest
as stated in wikipedia:
“An E1 link operates over two separate sets of wires, usually twisted pair cable. A nominal 3 Volt peak signal is encoded with pulses using a method that avoids long periods without polarity changes. The line data rate is 2.048 Mbit/s (full duplex, i.e. 2.048 Mbit/s downstream and 2.048 Mbit/s upstream) which is split into 32 timeslots, each being allocated 8 bits in turn. Thus each timeslot sends and receives an 8-bit sample 8000 times per second (8 x 8000 x 32 = 2,048,000). This is ideal for voice telephone calls where the voice is sampled into an 8 bit number at that data rate and reconstructed at the other end. The timeslots are numbered from 0 to 31.”
whether it’s speech, data or signalling it’s always the same principle. This is layer-1, it doesn’t care what is being transported…