6.10.4 Change, User-Opt, Operation, TERRESTRIAL Menu

Terrestrial: 1:PCM Bearer CRC

BER monitors: 2:Tx/Drop mux 3:Insert mux

Change, User-Opt, Operation, Terrestrial Menu

PCM BEARER CRC This option is only applicable when the unit is configured for Drop/Insert operation with a PCM bearer which supports CRC (T1-ESF or G.732). When appropriate this accesses a sub menu which is discussed in the following section.

TX/DROP BER The source for the estimate of the terrestrial BER at the Drop Mux may be selected:

Auto The selection is made automatically from the most appropriate source.

FAW The input BER is estimated from the Frame Alignment Words (FAW) of the PCM bearer.

CRC The input BER is estimated from the number of CRC errors (T1- ESF & G.732 only).

E-BitsThe output BER is determined by counting the E-Bits on the incoming G.732 signal. On a G.732 link an E-Bit is returned by the distant equipment when it receives an errored CRC, ie the incoming E-Bits represent the error rate at the far end of this modems outgoing G.732 link. Effectively the error

rate on the outgoing link at the far end.

Default: Auto

RX/INSERT BER The source for the estimate of the BER from the terrestrial port at the input to the insert mux may be selected as described above for the Tx/Drop BER. Default:

Auto

6.10.5 Change, User-Opt, Operation, Terrestrial, PCM BEARER CRC Menu

PCM Bearer: 1:Bearer CRC 2:E-Bits 3:CRC/Frame Acq'

Change, User-Opt, Operation, Terrestrial, PCM Bearer CRC Menu

BEARER CRC

This option, only applicable to G.732 Drop/Insert bearers selects if the PCM

 

bearer has a CRC, the options available are None/Ignore or Process. Default:

 

None/Ignore.

E-BITS

If a G.732 Bearer with CRC set to Process as above, then the additional option

 

to process & return E-Bits is also available, options for what happens when

 

incoming CRC errors are detected are No Action or Return E-Bit. Default: No

 

Action.

CRC/FRAME

 

ACQ'

Again, if a G.732 Bearer with CRC set to Process, then the option exists to

 

implement the strict letter of ITU G.704, and force a re-acquisition of the terrestrial

 

Drop/Insert frame sync if CRC sync cannot be achieved within 8ms. Options

 

available are Normal or Reacquire frame if CRC sync lost. Default: Normal.

P300H

P300 Series Modem Installation and Operating Handbook

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Paradise P300 specifications Change, User-Opt, Operation, Terrestrial Menu, Default Auto, Bearer CRC, Bits, Crc/Frame Acq