[Windows Central Question]

I use Pyrotrans() to automatically send and receive files between PC's. My windows 10 PC with a USB modem works when I use the phone line at my office but not with my phone line at home. It connects ok to the remote modem but they don't seem to want to "talk" to each other. If I use the same modem on the same line from a Vista PC it works every time????? I've had the phone line tested and it's OK.
Help please.