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polygonfuture
August 6th, 2017, 11:23 PM
Hi all,

I am new to this forum. I recently acquired an IBM 3178C terminal and had a couple questions.

I notice the terminal display uses a DB15 connector. Does anyone know if I can find a pinout for this connector? Is this RS232?

Is it possible to adapt these types of display units to work with a 5150 PC?

Trixter
August 7th, 2017, 09:59 AM
Based only on pictures, and of the monitor displaying some text, it looks like the monitor is a typical MDA monitor. Once you find the pinout and wire up an adapter, it should be possible to use it with an MDA/Hercules adapter in a 5150.

polygonfuture
August 7th, 2017, 10:29 AM
Based only on pictures, and of the monitor displaying some text, it looks like the monitor is a typical MDA monitor. Once you find the pinout and wire up an adapter, it should be possible to use it with an MDA/Hercules adapter in a 5150.



They look identical to the 5151 monochrome displays from IBM but it uses a (what I think) is a db15 serial plug that provides power to the monitor from the base unit.

You can see photos here.

40196

40197

g4ugm
August 7th, 2017, 11:27 PM
Typically the 3178 terminal has a BNC connector that's used to connect it the mainframe. Its pretty much useless without a 3174 controller. No idea what the 15-way is, unless its for twinax which was used on System 3/36/38 and AS400 in which case you need one of those to connect it too. So does it have a BNC COAX and how are the function keys labelled on the keyboard?

polygonfuture
August 7th, 2017, 11:57 PM
Typically the 3178 terminal has a BNC connector that's used to connect it the mainframe. Its pretty much useless without a 3174 controller. No idea what the 15-way is, unless its for twinax which was used on System 3/36/38 and AS400 in which case you need one of those to connect it too. So does it have a BNC COAX and how are the function keys labelled on the keyboard?




The logic base has a BNC connector. I'm interested in how the monitor itself communicates with the base. (Aka is it a serial rs232 db15 connector or some other protocol)

Here are photos of the connector to the monitor and the logic unit.

4020040201

David_M
August 8th, 2017, 02:21 AM
Typically the 3178 terminal has a BNC connector that's used to connect it the mainframe. Its pretty much useless without a 3174 controller. No idea what the 15-way is, unless its for twinax which was used on System 3/36/38 and AS400 in which case you need one of those to connect it too. So does it have a BNC COAX and how are the function keys labelled on the keyboard?

Yes the 3178 needs a cluster controller and the cluster controller needs a Mainframe.

Trixter
August 8th, 2017, 08:39 AM
I don't think the OP wants to connect the terminal and use it as a terminal -- I believe he's inquiring if the CRT portion of the terminal can be used as a CRT with an IBM PC.

g4ugm
August 8th, 2017, 09:58 PM
I don't think the OP wants to connect the terminal and use it as a terminal -- I believe he's inquiring if the CRT portion of the terminal can be used as a CRT with an IBM PC.

Yes, I was confused because he asked was it RS232. I don't have a pinout for the DB15, and its ages since I saw a real 3278, my terminals are Nokia "clones". I suspect it carries both power and video. No idea on the sync rates either, perhaps similar to EGA?