Before revision: Other similar types In addition to Twin-lead , two-conductor parallel wire line comes in two additional forms Window line 220px|alt=Nominal 450Ω window line|Nominal 450 ohm "window line".
After revision: Window line and ladder line In addition to twin-lead , two-conductor parallel wire line comes in two additional forms Window line 220px|alt=Nominal 450Ω window line|Nominal 450 ohm "window line".