Cisco IP Phone cannot hear individuals on either end.

I should have added that it works find when the only device connected to the wall jack. When daisy chained with computer then it has issues with each caller hearing the other. Unfortunately it has to be daisy chained with the computer as there are no other jacks available.

You daisy chaining it the correct way. The IP phone has to be plugged directly into the wall jack, and the port  from the phone plugs into the computer. You said it works fine when it is not daisy chained? Was it working before and all of a sudden it quit working?

No. I am replacing the phone that was there.

the phone you are replacing with this new one was not working either?  The cisco software loads up and the phone rings but users just can not hear each other, it is if both the speaker and microphone are muted... but they aren't? You say it works fine when they are not daisy chained? have you tried updating the firmware on the phone?  is this the same phone model as the phone that you are replacing?

The phone was updated before installing in its current location. It was tested in the shop connected only to the wall jack and worked fine.
Connected to the wall jack in its current location, it worked fine as well. Once daisy chained to the computer, it doesn't work properly. We had a working phone daisy chained at that location, but needed to move it to another location.