ST26 digital phone set is compliant with all Karel DS200 Series PBXs and IPV50 PBX Comfort and rapid use with the handsfree, handset and headphone options. 16 double function, programmable keys with embedded LEDs for monitoring the status of the assigned extensions / lines. 6 special functions keys (menu, park, phonebook, flash, transfer, and redial) that allow easy access to the frequently used features. 4 volume control keys (handsfree, volume increase and decrease, mute). 4 lines x 20 Characters LCD display providing comfortable use with 4 soft menu keys.