P300H
P300 Series Modem Installation and Operating Handbook
Page 135
7
MENU SCREENS FOR SPECIALIST OPTIONS
The following sets of menu definitions are shown in this separate section in order not to complicate the
earlier section dealing with basic menu operation.
7.1 CUSTOM FRAMING MENUS
These features are only available if the `Custom Features` feature is available together with the
corresponding IBS or IDR options (standard on P300-TCM). Refer also to the section
Closed Network
Plus ESC
via the Custom Service menu in section 8.7.2 on page 150.
7.1.1
Change, Tx/Rx, Service, CUSTOM Menu
If
Ý«-¬±³
is select from the Change, Tx/Rx, Service menu, this leads to the following dialogue:
Custom framing based on: [?]
1=IBS 2=IDR
Change, Tx/Rx, Service, Custom Menu
×ÞÍ
This leads to variants on standard IBS framing (all explained later) which allow for
operation:
Without a TS32 multiframe
Without a backward alarm
With four backward alarms for Multidestinational IBS
Minimum overhead mode
, where the overhead scales to provide any
ESC requirement at any data rate.
×ÜÎ
This leads to variants on standard IDR framing (again explained later) which
allow for operation:
With overheads of 96, 64, or only 32 kbps.
With 16kbps ADPCM on the audio channels instead of 32kbps,
allowing either all normal IDR features in a 64 kbps overhead, or (again
utilising 16kbps ADPCM)
96 kbps overhead with all normal IDR
features, but including a 32kbps spare channel for continuous
BER traffic quality monitoring.
The discussion of IDR this continues after the IBS section in para 7.1.3 on
page 137.
7.1.2 Change, Tx/Rx, Service, Custom, IBS Menu
If
×ÞÍ
is select from the menu above this leads to the following question:
Multiframe: [?]
1=Normal 2=Without a TS 32 Multiframe
Change, Tx/Rx, Service, Custom, IBS, Multiframe Menu
ÒÑÎÓßÔ
A TS32 Multiframe is used as normal.
ÒÑ ÌÍíî ÓÚ
No TS32 Multiframe is sent (Tx) or acquired (Rx). This is primarily for operation
at low rates where the TS32 multiframe becomes long enough to affect
acquisition time. For example at 32kbps the multiframe lasts 1 second, and
hence TS32 MF acquisition may take 1 second on top of demod lock time. This
selection also frees up one additional bit of the overhead (TS32 bit 4) to carry
ESC information.
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