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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.
