With a simple menu and explanatory text the 4501 is extremely straightforward to navigate. Functions are clearly depicted on the 4 line LCD display even in low light conditions. Line 1 shows the input signal, line 2 shows the units, and line 3 shows analogue output or tag number. Line 4 shows the communication and relay status. In addition the 4501 features password protection. Programming access can be blocked by assigning a password which is conveniently saved in the 9203B transmitter. This ensures a high degree of protection is maintained and prevents any unauthorised modifications to the configuration.