CU43PROG programming head. This is like a normal CU 42 head, only it's bright red in colour. The 'Red Head' is used to configure the radio and is also required to run the software. This, apart from its striking colour, is not dis-similar to the standard CU42 head. To upgrade a CU42 head to service level, a binary is programmed into an EEPROM and then the EEPROM is soldered into place in the head. A resistor is also added. You might then want to take the head down the paintshop for a re-spray. There is also PC software for the R40 as you would expect for a radio of this era. It's called Amanda and I'm told this has hardware copy protection in the form of a Sentinel parallel port dongle.