NEC EDK 21 B48
NEC EDK 21 Basic
NEC EDK 21 w/ expansion cabinets
B48: 48 Ports
Basic: 64 Ports
Basic with Expansion Cabinets: 192 Ports
Products
Telephone System
Telephone System
Products Telephone System
NEC EDK 21 Telephone System 
B48: 48 Ports