Are there recommended settings for the FXO ports on the SPA400; line impedances, transmit & receive gain etc.?
I need to interface to a legacy PABX and would like to do so using the SPA9000's FXS ports. The PABX requires line supervision to operate properly in the desired manner and gives me ROI or ROA options to do so. Is this possible, and if so which settings do I need to adjust to accomplish it?