Checking if a telephone dial is within spec without removing it from the phone.


I've previously written a blog post on using a Digital Oscilloscope to adjust the dial in a telephone, but it assumed the dial had been removed for stripping and cleaning prior to adjustment. I've recently been experimenting with some telephones to figure out the tolerances for both the Pulses Per Second and Make/Break ratio of the Grandstream HT8XX ATAs and wanted to check a dial without disassembling the whole phone.

I wasn't quite sure on the best way to go about it so I asked on the Telecommunications Heritage Group mailing list and James Campbell kindly replied with a simple way of checking the dial.