Linksys SPA921 Cisco SPA9000 Voice System Administration Guide - Page 268

SPA400 Field Reference Setup C Line Settings Transmit Gain Receive Gain Impedance Tip/Ring voltage Operational loop current Min On-Hook speed Ring frequency Min Ring frequency Max Ring Validation Time The gain level that the SPA400 may use to increase or attenuate the power level before transmitting to the telephony port NOTE Change this setting if remote call participants have trouble hearing the users of the SPA9000 Voice System. Make changes in increments of 3 dB; changes of less than 3 dB will not have a perceptible impact. Default: 0 The gain level that the SPA400 may use to increase or attenuate the power level before receiving on the telephony port NOTE The default Receive Gain settings should be satisfactory in most use cases. Unnecessary changes in Receive Gain can cause problems with echo. Default: 0 The impedance of the lines that are connected to SPA400's telephony ports Default: 600 Ohms The tip-to-ring voltage reserved for voice transmission Default: 3.5 Volts The minimum loop current that maintains an off-hook state. If the loop current drops below this value, the phone enters on hook state. Default: 10 mA The time that the loop current drops to 0mA when the phone enters the on-hook state. Default: Less than 0.5ms The minimum frequency of a valid ring Default: 10 The maximum frequency of a valid ring Default: 100 The minimum duration of a valid ring Default: 256ms SPA9000 Voice System Administration Guide 266