Anyone know the protocol for the remote control line on 80's era tape recorders?

Electronics
#1

Got myself a Tandy CCR-81 and been working on creating an RS232 interface for it. I’m fairly sure its going to be something simple, like a few pulses for stop, start, record, fast forward, rewind. but google dorking keeps giving either IR or vhs controllers and the model I have did not come with a controller (nor the 26-1207B/S-57 cable which doesn’t help anyways since it doesn’t generate the signals).

So I’m stuck trying to figure out the line protocol for the REMote/MICrophone Jack without anything to generate signals or to test with. Would anyone know what that protocol would be or where to find some details on it?

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#3

Guessing @richmeyer’s pillowcases have it printed on them? Helps with the “sweet dreams” thing.

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#4

Here is the User Manual with schematics. Hope you can find your answer here.
CCR81 Owners Manual.pdf (903.8 KB)

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#5

It’s on or off. You connect a cable from the rem port on the cassette player to a relay externally and close its contacts to turn on the motor. That’s it. That’s all. If the buttons are pressed then that function happens.

It’s used to allow you to put a tape in, press play and record, then type in the command on the computer to save the program. It’s also used with a switch on some hand-held microphones to turn the motor on or off, but you must again already have the play and record buttons down.

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#6

yeah… kind of. Three switches. 10^3 ohm resistance, 10^-6 mF capacitors:
S2: on :== play/record
S3: on :== FF/RW
S1a ~ S1f :== ???

#7

S1 is moved to R when you push Record. It switches the mode from playback to record

Rem is just a switch connection to turn the recorder motor on/off and have it do whatever switch(es) you have pressed.

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#8

hmm…

guess I need to pull out some tools at this point and see what is going on with record button depressed, etc… but if I’m hearing you right; Rem is just another switch that when pulled high? it activates the mode already set by the physical switches or turns on recording??

#9

Ten-year-old Matt can attest to the truth of this based on his numerous attempts to catch Santa Claus in the act using his dad’s Tandy cassette recorder.

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#10

I used one regularly with my TRS-80 Color Computer until I was able to afford a floppy drive.

#11

Not pulled high, just closed. It’s a 2-contact 3/32" (2.5mm) TS (Tip-Sleeve) phone connector that simply switches power on and off.

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#12

My intuition is that in order to automate it, robotics of some kind is involved.

Time for a decepticon themed tape recorder haha

#13

Uh… guess you’ve never paid attention to the Transformers cartoons, comics, and movies… Go read up on Soundwave.

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#14

You are way over thinking this.

Consider the classic earphone jack of an old transistor radio. Inserting the plug pushes a contact out of the way, disconnecting the built-in speaker from the audio amplifier and putting the earphone into the circuit.

The motor control on the recorder uses the exact same type of jack.

Every microphone I have seen, if equipped with a remote, has a molded cable end with two plugs. One for the mike itself and the other for the remote motor control. By default, the motor is connected to the power lead from the play switch.

When the mike or a separately available remote-only cable, is plugged in, the contact opens and the remote switch put in series into the motor circuit.

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#15

Soundwave was my mosted wanted transformer as a kid. Had both G1 Deluxe Optimus and scattershot but instead of soundwave I got doubledealer for my birthday.

#16

yeah I know I’m way to use to things like i2c or usb so the more simpler things are a brain puzzler for me but I think I get what everyone is saying; basically signal is already there on s1 and just need to close the loop to engage the motor.

#17

My thoughts are this: you merely need a cv/gate either with or without sync to relay… the gate or sync wojld close the switch and it starts whatever is pressed play record or whatever. Useful if you also have a klicker type module with passthrough.(which would take and generate a clock or sync off the audio signal going out)