Traditional 2 Prongs Intercom System Buying Guide:
- If your existing intercom is 2 Prongs, this is your exact REPLACEMENT. You can simply plug them into the SAME exact outlets.
- If you have a mix of 2 Prongs & 3 Prongs outlets in your house, You should buy this model.
- The difference between a 2 Prongs & a 3 Prongs intercom is Phase Bridging. In a word, with a 3 Prongs system, you don't have to search for an outlet that is in the same phase. The time needed to set up a 2 Prongs system ranges from 10 to 30 minutes depends on the number of units and the size of the building. The "2 Prongs Setup & Troubleshooting Guide" is included in the box.