The 606A1 CALLMASTER, called the CALLMASTER VI, works with an application software package, usually Lucent CentreVu Agent, through a connection with a PC.

The CALLMASTER VI is a miniature voice terminal which has two call appearance buttons with a red and green light beside each button, three feature buttons, two of which have an associated green light, a MUTE button and a HEADSET ON/OFF button which share a red light, and a blue RELEASE button. Other features can also be used according to the software application on the PC.