# Quick question

D

#### [email protected]

Jan 1, 1970
0
I'm trying to make an adapter between a parallel port and a device used
in psych experiments. The port on the device is a 15pin d-sub
connector (2 rows like an old game port, not 3 like a monitor)

I know that pins 1-8 on the 15pin connector are the data and that it
runs on TTL logic levels, but the data is supposed to be "inverted."
Would that typically mean that a 0 is on and a 1 is off, or would it
more probably mean that the least-to-most significant bit order is
flipped from the parallel port?

Also, in a version sold by the company for $200, the only additional feature is that it buffers the data because the port can be both input and output. However, if we're only ever using the input function of the port it shouldn't require a data buffer, correct? I can't really see paying$200 for a part that seems to just be an
adapater between two connector types and even in the picture on their
website looks like it's just electrical-taped or heatshrinked together.
(http://www.psylab.com/assets/images/Converter_copy.jpg)

I'd appreciate any help/opinions.

-Mike

D

#### Dan H

Jan 1, 1970
0
I'm trying to make an adapter between a parallel port and a device used
in psych experiments. The port on the device is a 15pin d-sub
connector (2 rows like an old game port, not 3 like a monitor)

I know that pins 1-8 on the 15pin connector are the data and that it
runs on TTL logic levels, but the data is supposed to be "inverted."
Would that typically mean that a 0 is on and a 1 is off, or would it
more probably mean that the least-to-most significant bit order is
flipped from the parallel port?

Also, in a version sold by the company for $200, the only additional feature is that it buffers the data because the port can be both input and output. However, if we're only ever using the input function of the port it shouldn't require a data buffer, correct? I can't really see paying$200 for a part that seems to just be an
adapater between two connector types and even in the picture on their
website looks like it's just electrical-taped or heatshrinked together.
(http://www.psylab.com/assets/images/Converter_copy.jpg)

I'd appreciate any help/opinions.

-Mike

Inverted usually means logically inverted as you describe

A parallel port usually needs some type of timing pulse to indicate
whent then should be sampled.

Dan

D

#### Daenris

Jan 1, 1970
0
Dan said:
Inverted usually means logically inverted as you describe

A parallel port usually needs some type of timing pulse to indicate
whent then should be sampled.

Dan

Well, the description says that pins 1-8 of the 15 pin are the data,
pin 9 is +5v and pin 10 is ground, the other 5 pins are unconnected. I
think that the experiment device is probably sampling that input
regularly to see what the signal is. The parallel port signal is
changed via a command in our experiment presentation.

-Mike

S

#### Si Ballenger

Jan 1, 1970
0
I'm trying to make an adapter between a parallel port and a device used
in psych experiments. The port on the device is a 15pin d-sub
connector (2 rows like an old game port, not 3 like a monitor)

I know that pins 1-8 on the 15pin connector are the data and that it
runs on TTL logic levels, but the data is supposed to be "inverted."
Would that typically mean that a 0 is on and a 1 is off, or would it
more probably mean that the least-to-most significant bit order is
flipped from the parallel port?

Also, in a version sold by the company for $200, the only additional feature is that it buffers the data because the port can be both input and output. However, if we're only ever using the input function of the port it shouldn't require a data buffer, correct? I can't really see paying$200 for a part that seems to just be an
adapater between two connector types and even in the picture on their
website looks like it's just electrical-taped or heatshrinked together.
(http://www.psylab.com/assets/images/Converter_copy.jpg)

I'd appreciate any help/opinions.

-Mike

I've got a page below that might give you some interface ideas
for the parallel port. I use the status lines for input, but you
might use a similar setup to input to bidirectional data pins and
save some \$.

http://www.geocities.com/zoomkat/status.htm

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