The P421 is a heavy duty watertight telephone for engine room spaces, galley and even for deck mounting. It can be hands free operated, and the hands free function is implemented using a unique digital signal processing technology.

It can be used for all PABX systems using plain analogue extension lines, but in conjunction with the AlphaConnect 48 / 128 systems, all the unique features are enabled. The display and keyboard have a red backlight with an automatic dimmer function sensing the ambient light level. The keyboard has a minimum number of keys that allows for single key calls to often used spaces such as Bridge, ECR, STGR etc. The telephone allows for direct calls, where communication can be established without any hands on by the called party. When used with the AlphaConnect 48 / 128 systems, the telephone receives public address calls and alarm calls.