Question { 4305 }

Which slot is reserved for GPRS?

Answer

Normally 8th slot is used for GPRS but it depends on us to
select the slot.

Question { 7235 }

Can we use 7GC instead of 15GC?

Answer

Yes we can use 7GC as an replacement of 15 GC but we can't use 15 GC as replacement of of the same because 7GC is used for long distance link as compared to 15 GC.

The difference between Tx Rx frequency in 7GC is 1610.

Question { TATA, 13666 }

What is VSWR?

Answer

VSWR - Voltage Standing Wave Ratio
This is the ratio of power transmitted by the TRx towards the antenna and the power reflected back to the TRx due to some mismatchings.It may be due to fault in connectors,jumpher or feeder or fault in antenna.Sometimes TRx may also be faulty.We can measure it with the help of VSWR meter or site master.

Question { 6657 }

Why the STMs in multiple of 1,4,16,64 ?

Answer

I think you have to study SDH network to understand the answer of this question.I am giving the formulae by which the STM-N is generated.

STM-64: 64 VC-4 or 16 VC-4-4c or 4 VC-4-16c or 1 VC-4-64c
STM-16: 16 VC-4 or 4 VC-4-4c or 1 VC-4-16c
STM-4: 4 VC-4 or 1 VC-4-4c
STM-1: 1 VC-4


Higher-level STM-N frames can be simplistically perceived as *4 multiples of a basic STM-1. An STM-4 is constructed by byte-interleaved multiplexing of 4 STM-1s into a frame that is 9 rows by 1080 columns wide. The STM-4 signal has a line rate of 622.080 Mbps (4 * 155.520 Mbps). The four STM-1s (STM-1(1), STM-1(2), STM-1(3), and STM-1(4)) are frame aligned before multiplexing. Frame alignment is achieved by ensuring that the first 12 bytes of the STM-4 signal are A1 framing bytes drawn from STM-1(1), the next 3 from STM-1(2), then 3 from STM-1(3), and finally 3 from STM-1(4). The 12 A1 framing bytes are followed by 12 A2 framing bytes that are obtained from the 4 STM-1s in a process, similar to the way that the A1 bytes were obtained.