Telephone Flashcards
What standard should be used for grounding in the PBX room?
TIA 6070
What is the difference between a station trouble and a system trouble?
Station trouble affects one station. System trouble affects two or more stations.
What are the nominal voltages for alerting and battery in the U.S.?
-48VDC
Explain the difference between a line and a trunk.
Line is the path between a switching machine and end device.
Trunk is the connecting circuit between switching machines.
Which telephone connection always has a 0 Volt measurement, Tip or Ring? Explain
Tip - First connecting point (grounds circuit)
Explain what happens during an Off-Hook and On-Hook event.
Off-Hook closes tip/ring loop to generate a service requests. On-Hook opens loop.
What are the three topologies for laying out a telephone system and how are they different?
Open Loop - least reliable; Closed Loop - more reliable, has return data; Homerun - easiest to troubleshoot.
Define the three main characteristics of ISDN.
End-to-end digital connection, common channel signaling, and multi-purpose user interface.
What three functions does the PBX control?
- Connects separate telephone circuits
- Provides information for accounting purposes using SMDR (simple metadata registry).
- Maintains uninterrupted, secure connection.
When discussing an EKS system, how do you denote capacity?
The amount of CO/PBX trunklines and maximum of station ports the system can accommodate
trunks / stations XX/YY
What is the difference between a hard key and a soft key?
Soft keys are programmable; hard keys are not.
List the three major components of a PBX.
common equipment, co trunks, station lines
What are the advantages of using a butt set?
Not only do they let technicians test line functionality, but they also allow contact with the central office to execute diagnostic tests or generate a call to speak with people inside or outside the building. Prevents mistaking a digital circuit for a voice one
What do switchtails provide a connection between?
PBX cabinet to connecting blocks (distribution frame)
How is grade of service defined?
The probability of a call being blocked or delayed for more than a specified interval.
