Nortel Compact 3x8 with Power Supply & DR5.1 Software NT5B05CP-93 (Refurbished)This Norstar KSU is a 3 line, 8 station PBX phone system unit designed for smaller business operations that need a system for optimal functioning, but do not need expandability that come with bigger system. These businesses usually are need of phone system features, such as paging and transfer, but do not need something too large. It supports all Norstar and Business Series telephones, including fully featured digital functions with LCD and soft keys.