ADDS 4000/260 keyboard connector

Longest of long shots, but does anyone happen to know the keyboard connector pinout on an ADDS 4000/260 terminal? I have such a terminal here, and it has a 6-pin RJxx-type socket, but the keyboard which came with it would appear to be for something else, and has a 4-pin RJxx plug (I'm not sure of the actual RJ designations, but they're physically different, albeit close - the keyboard one fits in the terminal's 6-way socket, but is too loose to make contact on its 4 pins) However, the manual for the terminal mentions supporting a PC keyboard, so it's possible that a standard PS/2 keyboard with the PS/2 connector lopped off and replaced with a suitable RJxx connector would work - i.e. the clocking method and scancodes are identical - if I knew the pinout (it's also possible that the same is true of the keyboard that came with it - the physical layout's identical to a PC, but with the addition of a 'select' key) cheers Jules