[ct-user] do you have a TS-940 with IF-10B installed?

[Eric Scace]

Hi everyone --

   Do you have a TS-940 with the IF-10B board installed?  If so, could you
take a few simple measurements?

   I'm debugging my TS-940 interface to the computer.  The radio has the
IF-10B board installed inside.  But the voltages present on the 6-pin ACC
connector at the back of the radio does not make sense, when compared with
the documentation.

   Before I tear into the IF-10B itself (or replace it), I'd like to compare
my measurements with someone who has a properly-functioning TS-940-computer
interface.

   Here is what I measure with a high-impedance voltmeter at the 6-pin round
DIN connector (no connection to any external level converters; i.e., just
voltages presented by the IF-10B to the outside world):

pin 1:  documented as "signal ground".  measures +0.07v against chassis
ground.

All other pins are measured against pin 1:

pin 2:  documented as "RXD-bar".  appears to float, as it should if it is a
data input lead.

pin 3:  documented as "TXD-bar".  measures +5.01v.  This seems wrong to me.
TXD should be held at a 'mark' condition until there is something to send.
So TXD-bar should be the inverse of that, or 0v??

pin 4:  documented as "CTS".  measures at +5.01v.  That also seems odd: CTS
is a signal input, not output.

pin 5:  documented as "RTS".  measures at +5.01v.

pin 6:  documented inconsistently as VDD (TS-940 service manual) and NC
(IF-10 documentation in Japanese).  Mine measures at +0.02v, which argues
for "NC" (not connected).

   Do you measure the same voltages?

   Thanks!

-- Eric K3NA


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