I have an Executone IDS 84 System with a CPU Labeled P/N - 22400-1 CPU/VCM and two 22550 Line/Station Cards, can someone tell me what CPU/VCM stands for and how can I reset the system to default without diconnecting the backup battery on the board, also does this system require an external Voice Mail or is it also a slide in Card, all I have for a phone set to program with are the Model 32 - 84500 18 Button Phone, will one of these work?