The maximum capacity of the Southwestern Bell FS 246 KSU is 6 lines and 16 stations. The system is divided into 3 parts: the KSU, station and power supply, all of which can be installed on the wall or on the desk anywhere due to the compact and unique design. The Southwestern Bell FS 246 KSU holds the FS cartridges. The Southwestern Bell FS-800 and FS-900 phones work with this system. The power supply of the Southwestern Bell FS 246 KSU keeps the heat out of the KSU for longer component life. This KSU is sold as 2×4 (2 line, 4 stations) and includes the power supply. Additional cards must be purchased separately to increase the capacity of the system.

• 2 lines x 4 stations
• Expandable to 6 lines and 16 stations by inserting FS10, FS20 and FS30 optional cartridges