ProtectNet PTEL2 OR PNET1GB ??

[Anonymous user]

I have a phone/internet connection FTTC VDLS2 (bandwidth frequency: 17-35 MHz), with a "Technicolor 768600" gateway (router+modem).
On the wall there's an outlet with 2 phone jacks (RJ-11 ports); a light gray cable comes out of the 1st port, with only 2 wires and the two central pins (n. 2 and 3), which plugs into the gateway VDSL2 port ; from the other port of the outlet a black cable comes out, always with only 2 wires and two central pins (n. 2 and 3), which plugs into the gateway LINE 1 port (IN).
At the gateway LINE 2 port (OUT) a phone cable connects a fax modem inserted into my PC, a fax machine / printer multifunction to which the telephone and the t.a.m. are connected.
The gateway PSTN port is empty.
The gateway Ethernet port 1 is connected, by an Ethernet cable, to my Switch port 1. To the other 7 Switch ports the various network devices are connected: PC, scanner, etc.

To protect the fax modems, the gateway (router+modem) and the ethernet/switch network from overvoltages, do I have to use the APC ProtectNet for phone lines PTEL2 OR the ProtectNet for Ethernet lines PNET1GB ? Or both of them?
Where should I mount it/them ?
Thanks for the tips.