[comp.sys.ti] 99/4A cassette port pinouts requested

lotto@midas.harvard.edu (Gerald I. Lotto) (01/17/90)

I have been asked by a TI 99/4A owner to help with a stolen "drive".
From the description, this drive sounds like a cassette player. The
cable is gone as well. He has no documentation and I have not seen the
machine. My questions are...

Can I make an adapter cable for any cassette player that will enable
him to read his tapes?

What kind of connector does the machine have and what are the pinouts?

Respond via e-mail if possible... lhasa is not a uucp or BitNet site,
but mail to lotto@husc6 (both uucp and BitNet) will work as well.
Thanks.
--
Gerald Lotto <lotto@lhasa.harvard.edu>     "Have you hugged the curves today?"
Chemistry Dept., Harvard Univ.                         AMA #520019

young@pur-ee.UUCP (Mike Young) (01/18/90)

	Yes, just about any cassette player will work. If all you want is
to read the tapes, you need a plug to fit the player's earphone jack. Many
players also have a motor-control jack (frequently a submini phone jack); this
can be used IF its polarity is correct. If not, no problem; it's optional.

	The connection to the 99/4A is a 9-pin "D" connector on its backside.
Don't confuse it with the 9-pin D on the side - that's for the joysticks.

	Pin	Function
	___	________

	 1	motor control, cassette 1 center conductor
	 2	 "	"	 "	" shield
	 3	microphone connector ground return (shield)
	 4	N/C
	 5	mike connector center conductor
	 6	motor control, cassette 2 center conductor
	 7	 "	"	 "	" shield
	 8	earphone connector center conductor
	 9	  "	    "	   shield	


	The microphone connection is only used for recording data onto the tape.
In the stock TI cable, Cassette 1 gets earphone, mike, and motor control conn-
ections; Cassette 2 only gets motor control and mike. The TI Basic cassette
routine also forbids you to read from cassette 2.

	I recommend using a battery-operated recorder to avoid possible AC
line interactions, and avoid AC hum as well.

	Hope this helps.

						Mike Young
						Purdue University EE Dept.
						W. Lafayette, IN 47907

						young@ecn.purdue.edu
						...!pur-ee!young