I'm new to this Strata 424 system with AMANDA VM.
One or more Single Line Telephones "ping" -- a short ring every second or less in sync with the clickety-clack of the relays in the auxiliary cabinet where there are four RST2U cards. Why are these phones doing this, and how do I make them stop?

I have one spare card -- RSTU3 -- is this a direct replacement for the RSTU2?

Thanks in advance.

John Sperr
Rhinebeck NY