> The modem didn't come with a telecom-style phone plug, so I'm using > the same one from my dial-up modem: male telecom - male rj-11 (or > whatever number that is). The splitter is male rj11 - (female rj11 > phone/female rj11 ADSL). I've also got a male rj11 - male rj11.
You need the filter as it has an RJ11 socket for the ADSL router and BT for the phone.
