The Digital Business Phone [Alpha] EX Series supported a digital public network of INS Net64. This series had streamlined wiring because of its digital bus wiring method. The system based on this series allowed system cordless telephones to be used in up to four overlapping speech zones (about 100 meters each). The cordless phones could therefore be used in a broad area by moving from zone to zone. This series also had a scramble feature to help protecting against eavesdropping. There were many types of options available. In addition, This series supported remote control for setting and updating various data items.