AT&T 555-600-736 manual GROUND-START Trunks Potential Problems

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GROUND-START TRUNKS:

POTENTIAL PROBLEMS

There are very few problems that can occur when properly functioning ground-start trunks serve a properly administered PBX, since modem PBXs and ground-start trunks were literally made for each other. This Application Note does not cover the kinds of problems that can occur when a trunk develops a problem and no longer functions properly. Suffice it to say that a malfunctioning ground-start trunk may behave just as poorly as a malfunctioning loop-start trunk, but a properly functioning ground-start trunk will always outperform a properly functioning loop-start trunk.

It’s possible that when a large key system customer upgrades to a PBX, the conversion from loop-start lines to ground-start trunks may extend the installation interval. It is still always best to convert, and accept the one-time inconvenience, in order to enjoy a much better grade of service over the long haul.

The most common installation problems involved with ground-start trunks are reversed Tip and Ring connections and improper grounding of the PBX.

GROUND-START TRUNKS:

WHEN TO USE GROUND-START TRUNKS

Ground-start trunks should be used for a MERLIN LEGEND Communications System when configured as a PBX.

They offer the following major benefits:

1.The Tip ground seizure signal virtually eliminates the possibility that a two-way trunk can be seized from both ends simultaneously.

2.The “window of opportunity” for glare is reduced from four seconds to a small fraction of a second.

3.Ground-start operation also provides a positive indication of network disconnect when programmed at the CO for Calling Party Control, allowing a PBX to disconnect a station when the outside party on a call hangs up.

4.The possibility of a user circumventing toll restrictions is eliminated.

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Contents AT&T Merlin Legend Communications System Application Notes Page Merlin Legend Trunking Concepts Application Note Index Introduction to Trunking Concepts TIP and Ring ExplainedLines and Trunks LOOP-START Trunks Operations LOOP-START Trunks POTENTIAL-PROBLEMS Problem of GlareAutomated Attendant Ghost Calls and Loop-Start Facilities LOOP-START Trunks When to USE LOOP-START Trunks Proper Loop-Start Facility ApplicationsUnavoidable Loop-Start Facility Applications Cost GROUND-START Trunks Operations GROUND-START Trunks Potential Problems GROUND-START Trunks When to USE GROUND-START TrunksDirect Inward Dialing did Trunks Operational Characteristics Did Trunk Signaling Characteristics Types of Loop Reverse-Battery SignalingAdministration Considerations in Using did Trunks When to USE did Trunks TIE TrunksSimple Tie Trunk Operation Tandem Tie Trunk Operation Signaling and Implementation TIE LinesTransferring Calls P E Transmit C E I V E ON-HOOK OFF-HOOK OFF Premises Stations Page DS1 Service Overview and OperationsDESIGN, Signaling & Implementation Potential Problems/LimitationsData Communications Equipment Do GBS Customers Need T-1?Channel Service Unit CSU Multiplexer MUX DS1 Facility Services IsdnSDN SID/ANI Maintenance and Troubleshooting Special HOTEL/MOTEL TrunksOperation Overview Hardware Module LINE/TRUNK Station Type Specifications TTR Trunk analog voice Reusable Modules from Merlin II R3 Administration ConsiderationsReferences