Got a fun one here.
a simple Partner Plus 3.1 CPU, nothing fancy.
Ext 13's keypad started to fail for buttons 3,6 & 9.
Resetting the phone fixes problem for a few hours, then trouble returns.
Swapped phones (and line cords)- problem followed.
Swapped ports @ KSU - Problem followed.
Installed new telephone and cord - problem continues.
Double checked connection and RJ45 at KSU / MDF - all looks good.
Cannot see any corrosion or twisted cabling.
The only constant in this problem is the actual cabling, which I've never heard of causing this type of problem.
Cannot change pairs on cable due to another ext already using those pairs.
(That ext is working fine w/o issues.)
My next step is to locate some chicken bones to remove the evil spirits.
Anyone had this trouble before on a Partner Plus?

Thanks
Gonzo