CaptSteveT,
Unfortunately the 12p to 10p adaptor cable cannot be used. Internally the make up of this cable is different from that of the TZ3-12P-PGT cable.
So the 165T/265LH-PM488 needs to be returned /exchanged from the place of purchase for the 165T/265LH-PM488-12P version of the transducer, or the other option is to add the above TZ3-12P-PGT cable to the end of the cable.