PBX Systems
PBX Systems
Branch Exchange Switches
PBXs, KSUs, and PABXs contain line cards that support various transmission protocols
such as ISDN, T1/E1, HDSL, and ADSL (Figure 3.31). PBXs also have features such as a
POTS (plain old telephone service) pull-through which allows stations to have outside line
access in the event of power failure. All incoming lines to the PBX are subject to
environmental hazards such as lightning and power cross.
To Network
Station Primary
Protection
Logic
POTS
T1/E1
ADSL
HDSL
ISDN
PBX
Stations
Figure 3.31 PBX Overview
Protection Requirements
Branch exchange switches should be protected against overvoltages that can exceed
800 V and surge currents up to 100 A.
The following regulatory requirements apply:
•
•
TIA-968 (formerly known as FCC Part 68)
UL 60950
Branch Exchange Reference Circuit
See the following sections of this data book for interface circuits used to protect of PBX line
cards:
•
•
•
•
•
•
For POTS protection, see "Customer Premises Equipment (CPE)" on page 3-3.
For ADSL protection, see "ADSL Circuit Protection" on page 3-7.
For HDSL protection, see "HDSL Circuit Protection" on page 3-8.
For ISDN protection, see "ISDN Circuit Protection" on page 3-10.
For T1/E1 protection, see "T1/E1 Circuit Protection" on page 3-14.
For Station Protection, see "Analog Line Cards" on page 3-17.
© 2002 Teccor Electronics
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SIDACtor Data Book and Design Guide
TECCOR [ TECCOR ELECTRONICS ]
