Need help connecting my HP 7603 AIO to Gateway XB6 so I can fax. Tried called Xfinity to find out which things were on 2.4 GHz or 5 GHz?

I checked the Xfinity app and it's connected to 2.4 GHz which HP stated it need to be set up to that because it will not fax if it's on 5 GHz.  I have one phone line and it's shared with the printer.  I have my phone set to answer in 2 rings and my fax/printer to answer in 5 rings.  I was told to have a 2-pin (2 wire) phone cord to connect.  However, when I try to hit the fax on the printer, I don't get a dial tone but if I disconnect and test the same phone cord with my phone there is a dial tone there.  I bought a HP 7602 and had the same issue, so I was told that the fax port was probably defective.  So, I called HP and they returned that printer and sent the HP 7603 and stated they were not seeing any faxing issues with that printer.  On the back of the HP Printer where the two lines are they are not labeled 1-Line or EXT but have these pictures of a telephone on the right side (if standing in front of the printer) and the other port on left side has a picture, not sure what it's supposed to be, hard to make out........trying to figure out which port should be for the fax and what port should be connected to my house phone.  I do currently have a dial tone with my house phone but not the printer.

Also, many fax machines can't tell the difference between long-distance and local calls. You will want to always dial 1 before the area code to ensure a proper connection.

Here are some additional Troubleshooting your Xfinity Voice and fax machines recommendations. 

So, just now I disconnected all phone cords and connected just one cord from the Gateway telephone port to just the one port on the printer for the fax.  Tried to see if I tried to enter a number in the fax if I would get a dial tone just with one cord connected; no dial tone detected.  So, I ran a Fax Test and the following passed; Fax hardware test, fax connected to Active Telephone Wall Jack, Phone Cord Connected to Correct Port on Fax, and Using Correct Type of Phone Cord with Fax.  The things that failed was Dial Tone Detection and Fax Line Condition Test --both Failed.  Fax Line Noise Test -- Not Run?

The ports on the printer are not listed as 1-Line or EXT.  on the one side is a picture of telephone and the other is a picture of what looks like a spot you plug into the phone.

I would ensure you have a phone line from the Xfinity Gateway TEL 1 port (top left) to the printer/fax left port with the telephone icon. That appears to be the incoming port, and the other port can be connected to a phone.