Thanks to the 30 freely programmable keys, including LED support, which can be assigned in two levels like the Sensorfon ST 56 (IP), the STE 56 becomes a valuable tool for anyone who needs to manage a variety of phone numbers and functions. This way, you can easily see which colleagues are currently on a call and perfectly coordinate incoming calls. The STE 56 can only be used in conjunction with the Agfeo system telephones ST 56 and ST 56 IP. A maximum of three STE 56 units can be connected to one system telephone. The total number of connectable STE 56 units depends on the communication system being used.