- Boost ringing on FXS ports or IP phone system analog ports that are weak or fail - Boost ring power on analog PABX/KSU stations that are weak or fail - Reshapes troublesome distorted ringing signals - True Sine wave ring signal output - Boosts ring to 4 REN - Caller ID compatible - Easy RJ-21X installation - Compatible with distinctive ringing services - Will not affect normal line operation - Reshapes troublesome square wave ringing - Fax and modem compatible - Not compatible with pulse dialing