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APPENDIX B
B-2
Larger networks with 56 kHz and 64 kHz circuits can also utilize the
CELP Voice Channel Module to maximize usage of bandwidth. Voice
channels at higher rates quickly absorb much of the data capacity, and
restrict the potential number of voice circuits. The CELP Voice Channel
Module may provide additional voice channels at 4.8, 6.4 or 9.6 kHz
without impacting the total bandwidth available for data. This capability
makes the CELP Voice Channel Module particularly well suited to
applications in
the
between dealer rooms in global trading networks (see Figures B-3 and B-
4).
The CELP Voice Module supports in-band E&M signaling. The pulse dis-
tortion level of 0.625 ms and the 20 ms minimum pulse requirement are
compatible with 10 pulse per second dialing systems the world over.
If the CELP Voice Module is used in an application which does not re-
quire E&M signaling, such as in open lines between brokers, then in or-
der to ensure that breaks do not occur in the voice path every minute due
to the requirement to retransmit the M lead information, the M lead must
be tied in the BUSY state.
There are various means available for forcing the M lead BUSY. One
way which may be considered is to configure the M Lead jumpers on the
base card as follows:
X1 —
One jumper in the GND position.
X2 —
One jumper in the INT position.
X3 —
One jumper in the INT position and one jumper in the
GND position.
X4 —
One jumper in the US position.
The FAX bypass feature connects FAX machines which comply with
CCITT Group 3 standards. This feature requires that the CELP Voice cir-
cuit is operating at 6.4 kHz. The actual FAX transfers will take place at
4.8 kHz. If the tail circuits are long then the FAX transfers may down-
speed, under control of the FAX machines, to the fallback rate of 2.4 kHz.
financial
community,
such
as
communications
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