[PROBLEM/SOLUTION] I have a new phone that goes straight into Hold on pickup

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Greg Ercolano

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Nov 26, 2019, 11:11:59 PM11/26/19
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> I'm trying to add a new phone to the KSU, and it goes directly into Hold when I pick up a line.
> What would cause this?


This happens when something is wrong with the A lead circuit.

It's staying open on pickup, instead of closing to ground, which simulates going into Hold on pickup.

Normally the A lead (e.g. Pin 27 for Line 1) is connected to ground (Pin 2) when a line is picked up; switch closures inside the phone connect the A lead to ground in the off-hook state.

When you press down Hold, T/R remain connected, but the A lead goes open, which together trigger a Hold condition at the KSU. When the Hold button is released, T/R are disconnected from the phone, leaving the call to be kept active by the KSU.

NOTE 1: A problem with pin 2 (common ground for all A leads) can affect ALL lines. So if all lines go into Hold on pickup, focus on pin 2 (O-W wire)

NOTE 2: When debugging such a problem, it's best to have a 1A2 amphenol pinout handy, as well as the BSP for your phone's model (example: schematic for a 2830)

Check the A lead circuit in the phone; using a test meter in continuity mode, test the amphenol connector across pin 2 (ground) and pin 27 (A lead for Line 1). It should tone when Line 1 is picked up, and stop tone when pressing down Hold or on hangup.

If the A lead doesn't close during pickup, that's the problem to solve. Using the BSP for your phone model, check the wiring of Pin 27 (W-O wire) through the switch contacts of the hook switch, hold button, and line button to Pin 2 (O-W wire) against the wiring inside the phone.

Possible problems:

· Amphenol connector contacts corroded
· Broken wire somewhere in the connector or phone for any signals involving the A leads
· Switch contacts for the phone's Hold button, Hook Switch, or Line Buttons not making proper contact
· Miswiring inside phone
· Miswiring between phone and KSU (extension, connectors, 66 blocks, etc)

If the A lead seems to work when testing the phone's connector, check any wiring between phone and KSU,
such as 66 blocks, 66E3 devices, etc. Focus on pins 2 and 27 (O-W pair) if Line 1 has the problem.

PS. This isn't covered in the manual (yet), but will be added to the Troubleshooting section.
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