Tadiran Telecom Coral IPx 800 Series, Installation Procedure And Hardware Reference Manual

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Common Control Cards
8-21
HDC C
a
rd
Hig
h
Den
sity Con
tr
o
l
8
Digital Tone Generator
The digital tone generator generates the audio call progress tones (dial, busy, ringback,
etc.) used to notify the caller of the status of the call. The tones are also used during
Keyset (FlexSet, GKT, DKT, DST, EKT, VDK, etc.) ringing (except for mute ring which
is a function of the telephone set itself). DTMF and MFC dialing tones and test tone
patterns used by diagnostics are also generated by the 4GC/32GC. These tones are
stored in digital PCM form, in a programmable PROM. The stored tone patterns are
sent directly to the digital PCM bus when required. See
page 8-23, Tone PROM
, below
for more information.
Time Slot Management
Each HDLC and PCM bus operates at a fundamental data rate of 4.096 Mbps. This
data rate allows each HDLC bus sufficient bandwidth to simultaneously control up to
64 peripheral bus controller circuits located on the Shared Service and Peripheral
cards.
Every PCM highway consists of a transmit bus and a receive bus, each of which are
divided into 64 time slots. Each time slot is eight bits wide, sampled every 125
microseconds (mS), or 8,000 times per second. This rate matches both American and
European PCM voice transmission rates to facilitate complete digital integration with
the local telephone network.
The time slot manager, acting on command by the system processor, is responsible for
forwarding PCM voice samples from an incoming transmit time slot assigned to one
port to a complementary outgoing receive time slot for the recipient port. Traffic
handling capacity of the HDC card is maximized through the use of a very
sophisticated algorithm to avoid time slot usage conflict.
Using Time Slots
A call between two ports requires one transmit and one receive time slot on a single
Peripheral highway. Therefore, the HDC card is capable of establishing a call between
64 ports on each of the eight peripheral highways to any other 64 ports, with a
maximum of 512 simultaneously busy ports, using the eight peripheral highways.
The HDC’s 512 x 512 Time Switch interfaces with the Coral cabinet using eight Receive
and eight Transmit PCM highways. Each PCM highway carries 64 Time Slots. The total
number of Time Slots for the Coral with the HDC is 512 for Receive and 512 Transmit
PCM highways. The Coral backplane is designed to have two Receive and two
Transmit PCM highways for every four card slots. See
Figure 8-3
.
Number of Transmit TS - 64 on each of the eight PCM highways, making a total of 512.
Number of Receive TS - 64 on each of the eight PCM highways, making a total of 512.
Maximum 384 simultaneous calls per Coral IPx 800 system.