Epson X-PRF 1000 - Manual (Page 15)

Plug one end of the telephone line cord (the flat cord) into the back
of the fax machine, as shown below.
Plug the other end into your modular telephone wall jack (USOC
RJ11C). Make sure both ends of the cord click securely into place.
Note
If you have the older 4-prong telephone wall jack, you
must use a modular 4-prong adapter USOC RJAIX). Plug
the adapter into the wail jack, and then plug the telephone
cord into the adapter, as shown in the illustration below.
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