IC-471. Digital output taken from discriminator (IC-14) pin 9. This pin, and
        ground, are brought out to J-14 for feeding the optional tone squelch
        unit (not fitted on my rig). Rig works well with existing CFW-455E
        filter (I think its 15KHz bandwidth) but needs retuning after about
        4-5 KHz of doppler; a wider filter may require less frequent tuning
        but, with the advent of 12.5 KHz channel spacing on terrestrial uses,
        I kept the narrow filter.

        Digital modulation would be applied, as with the IC-251, to top of
        the deviation pot; thats at the junction of R28 and R29, close to Q1
        on the circuit diagram. I haven't actually used this yet (see note
        above about RUDAK).

        PTT connection made to the appropriate pins on the rear panel's
        accessory socket - same story as IC-251.


Connections made to both rigs via phono sockets using screened cable both
inside and outside the rig. The IC-251 has some unused sockets, and the IC-471
has a removable plate which I mounted 3 sockets on.

The IC-471 provides receiver audio on pin 8 (the centre pin) of the mike jack.
I modified the IC-251 to put it on the same (previously unused) pin. This is
used for "ordinary" 1200 bps operations. Pin 4 of the IC-471's mike jack is
the up/down line; that pin is unused on the IC-251 so I'll probably use it
if/when I modify the 251 for up/down.

73 Richard G3RWL

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