Can't rec recording for one of our CP-7975G

[babydog58]

We need to rec recording for training purpose, ONLY one of the CP-7975G cannot be recorded, as no sound displays. No problem with other phones.

We record calls with SANYO JNC, by connecting with the port of hand set, and answering calls with handset. Any suggestions to solving the issue?

[Joseph Martini]

If the recorder isn't connected to the handset port of the phone and just a normal handset is connected does everything work properly?  If you move the recorder to a different 7975 phone does the recording work properly, meaning the does problem follow the recorder or the phone?  Since it sounds like an analog recorder I can't think of much other than possibly swapping the handset cable out with a working phone that could cause this assuming that connecting a regular handset works fine on that same phone.