Some fax machines have phones attached so that there is a way to access the phone line.
Fax signals transmit over phone connections, and all fax machines connect to a phone line to send and receive information.
A phone attached to a fax machine works the exact same way as a regular phone. You can dial calls out by pressing the keypad the same way as a regular phone. If the fax machine rings, you can pick up the handset to answer the call (this might result in the fax not being properly received).
Question: Do all fax machines have phones?
Answer: No, many do not. They are becoming relatively rare with newer models of fax machines.
Question: Can you attach a phone to a fax machine (or fax modem)?
Answer: Usually yes. A phone cord can plug into a port named “ext” (short for extension). Once connected, calls can be made from the phone as if it was directly attached to the landline outlet.