telephony Flashcards
what do switch tails provide a connection between?
the PBX and the distribution frame
how do system port circuits connect to station blocks
switch-tail connectors
what 3 things does a PBX supply
battery
ringing voltage
dial tone
when discussing an EKS system how do you denote capacity
first number is max trunk ports
second number is max line ports
system trouble
affects multiple users probably a pbx issue
pbx
private branch exchange
how is grade of service
probability of a call being dropped
tt568b pinout
orange green blue brown
what is the nominal voltage for battery
48 VDC
t568a pinout
green orange blue brown
wg g wo b wb o wb b
what are the 3 topologies
open-loop
closed-loop
hom-erun
what is the nominal voltage for alerting
90 VRMS
what is the transmission speed of a t-1 circuit
1.544mbps
home-run
a wire goes from NID to each device individually
what is the difference between a hard and a soft key
hard key cannot be changed
soft key can be assigned by software
station trouble
one user issue probably caused by cabling
open-loop topology
wiring ends at last jack
closed loop topology
wiring begins and ends at NID
list three major components of a PBX
common equipment
station
CO lines
what standard should be used for grounding in the pbx room
ansi tia eia 607A
what are the advantages of using a butt sett
tone and pulse operation
last number
redial
two way speaker phone
CO
central office
what happens during off hook and on-hook events
off hook closes loop. on hook opens loop
line circuit
connects end user to PBX (private branch exchange) or CO (central office)
trunk
connect PBX to PBX, CO to CO or PBX to CO
