Waht is an MC1806 ?

The Subject: line says it all really, but perhaps I should give a little more explanation. I am working on an HP59405, which is the HPIB interface for the HP9830 'calculator'. On the PCB are 2 chips which cross to something called an MC1806. This is not in any of my Motorola databooks. What I have determined (I think) so far : 1) 14 pin DIL package, power on 14, ground on 7 as usual. 2) Seems to be a quad 2-input device, pinout as the 7400 -- that is, inputs on 1 and 2, output on 3, etc. 3) Seems to be DTL in that the output directly drives the base of an NPN transsistor, the emitter of which is grounded. 4) The most logical (!) function would be a quad 2 input NOR gate. Maybe an AND gate? Does anyone have a databook that lists it? -tony