Paradise P300 User Manual

Page 103

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P300H

P300 Series Modem Installation and Operating Handbook

Page 103

Terrestrial: 1:PCM Bearer CRC

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

Change, User-Opt, Operation, Terrestrial Menu

PCM Bearer: 1:Bearer CRC

2:E-Bits 3:CRC/Frame Acq'

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

6.10.4 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-Bits

The 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

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

.

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