AC4830xC-C Data Book
Chapter 5. PCM Highway Interface
Revision 1.0
57
March 2000
5
PCM HIGHWAY INTERFACE
The AC4830xC-C supports connection to E1 trunks.
An E1 system is composed of individual timeslots, each timeslot, or channel, consisting
of eight bits, numbered 1 to 8. Bit number 1 is the MSB and is transmitted first. Bit
number 8 is the LSB and is transmitted last.
5.1 E1 PCM Highway
In a single E1 system there are 32 such 8-bit timeslots numbered 0 to 31, and a 2.048
MHz clock drives the communications, as shown below in Figure
5-1.
Figure
5-1: E1 Timing
P C M C L K
P C M F S
CHANNEL 31
(TIMESLOT 30)
CHANNEL 32
(TIMESLOT 31)
CHANNEL 1
(TIMESLOT 0)
P C M O U T
M S B
LSB
M S B
LSB
It should be noted that in the above case, PCMFS appears only in the 127
th
time slot.
When working with more than one AC4830xC-C, starting the operation should follow
this order:
1. Download the kernel and program codes to all AC4830xC-C chips.
2. Switch each of the AC4830xC-C chips into Run mode and configure the Time Slots
allocation of each chip
before
the next chip is switched into Run mode. This
procedure must be followed for all of the chips to prevent any overlapping of the
Time Slots allocation (default value for all of the channels is the same).
3. Switch the required channels to the Active state.
The above procedure ensures that no data is overwritten in the PCM highway.
Содержание AC4830 C-C Series
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