Ideal for realtors, secretaries, and receptionists, the PM200 Expansion Module adds extra BLF (Busy Lamp Field) buttons to P-Series IP phones for extra functionality. The PM200 Expansion Module is the perfect upgrade to the P330 or P370 IP phone, adding up to 60 programmable keys for contacts and functionality. Add up to six PM200 consoles to a P-series phone for a total of 360 extra keys.