The VG204 has 4x RJ11. The VG224 has a telco RJ21 interface (that houses all 24 lines) that you can break out to a punch-down block, or dedicated RJ21-to-RJ11

The VG204 has 4x RJ11. The VG224 has a telco RJ21 interface (that houses all 24 lines) that you can break out to a punch-down block, or dedicated RJ21-to-RJ11 boxes/panels/cables. In my case I have a breakout box with 24 phone jacks. A VG248 is the same thing, just with two RJ21 interfaces for 1-24 and 25-48.