Inter-Tel AXXESS Manual page 125

4.200 Compared to the other trunk cards in the system, the T1, E1/PRI, or T1/E1/PRI card is
very sophisticated and offers some unique programming options. The information that is pro-
grammed specific to each T1, E1/PRI, or T1/E1/PRI card installed in the system includes:
•
Framing Type: The type of framing scheme used by the T1 trunks connected to the
card can be D4 Superframe or Extended Superframe (ESF). The type of framing
scheme used by the E1/PRI trunks connected to the card can be Common Channel Sig-
naling or Channel Associated Signaling.
•
Zero Code Suppression Scheme: With a T1 Card, the programmer must select the type
of zero suppression scheme, AMI (bit-7 stuffing) or Bipolar Eight Zero Substitution
(B8ZS), used by the T1 span connected to each card. With an E1/PRI card, the system
allows this field to be programmed for either HDB3 or None. Note that this parameter
needs to match the configuration of the remote end of the E1 span to work properly;
therefore, verify that the remote end is configured in the same manner. Digital informa-
tion is transmitted over the E1 span as a series of 1s and 0s (e.g., 1000 0000 0000
0001...). If there are too many consecutive zeroes, the E1 clock extraction circuitry does
not operate correctly. To prevent this, E1 carrier equipment can limit the number of con-
secutive zeroes by using a zero-code suppression scheme. The system supports the
HDB3 type of zero code suppression, which should be selected for PRI to function cor-
rectly.
•
Line Build-Out (LBO) (T1 and T1/PRI Only): The programmer must designate the
LBO attenuation of the T1 span connected to the card. This value can be determined
automatically by the system, or it can be set according to the T1 provider's recommen-
dation.
•
CRC Processing (E1/PRI Only): The system allows CRC Processing to enabled or dis-
abled. Note that this parameter needs to match the configuration of the remote end of
the E1 span to work properly; therefore, verify that the remote end is configured in the
same manner. An optional cyclic redundancy check (CRC) has been incorporated
within the E1 bit stream to provide additional protection against simulation of the frame
alignment signal, and /or where there is a need for an enhanced error monitoring capa-
bility. CRC information is transmitted within the synchronization channel and also
requires a multi-frame synchronization process.
•
Reference Clock Programming: With a U.S. system, it is crucial that all T1 Cards and
the CPC or CPU card share the same clock signal so that they can remain synchronized
with each other and the T1 span. This is accomplished by allowing one of the T1 Cards
to act as the system reference clock. The programmer must designate whether the T1
Card is a private network master, private network slave, or a public network slave (the
public network always acts as the master clock). Cards that are used for clock recovery
from the network should always be located in the master part of a quad configuration.
With a European system, the system has several clocking options. However, whenever
the system is connected digitally to the network, it should always be a slave to the net-
work. Currently, E1/PRI cards are the only cards than can recover clock from the net-
work and provide it to the rest of the cards in a system, synchronizing all the system
cards with each other and making the system a slave to the network.
T1C, E1/PRI, or T1/E1/PRI Cards Features
® ®
INTER-TEL AXXESS MANUAL VERSION 11.0 – May 2008
Specifications
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