Help me identify a RS232 port/connector

[twoheartsinthedark]

Hi all, can anyone help me identify a serial port that I am at a loss. I have an old Blaze Braille and Speak with what I think are two independaant RS232 ports on the left side. I attached a photo. I would like to find or make a cable for this as I would like to use it as an external speech synthesizer. This braille and speak BS1is from around the late ‘80s or very early ‘90s.The “newer” Braille and Speak bs2 models from around 2000 used two round mini 8 pin DIN plugs with female connectors on the unit. This older model uses two square ports with male pins on the unit. What are these connectors called? I attached a photo. Thanks


Frank

 

[cj7hawk]

They resemble Molex power connectors - I've seen similar on Cisco routers. But uncertainty about the scale makes me wonder if I'm correct.

What is the pin size and spacing? Is it 0.1", 0.15" or 0.2"

If it's 0.1" you can use standard headers and make up a plug.

 

[Bruce Tomlin]

those are just dupont style 0.1" connectors (or IDC connectors), and who knows that the pinout is unless you can find it on google image search, it might not be RS-232, just TTL serial

(I actually have one lying around, but never had time to mess with it beyond dumping the ROM and noticing it has a Z180)

This is really all I know about it:

https://support.freedomscientific.com/Content/Documents/Manuals/Legacy/Braille_N_SpeakDocs/Braille_N_Speak_UserMan.txt

and it's probably 9600-8-N-1

 

[MiaM]

Agree that dupont single pin cables would likely fit.

IDC connectors for flat cables would likely not fit though, as there seems to not be enough space on the sides.

There were a type of connector where you crimped each wire individually, and weirdly there were no strain relief. Don't know what they are called though, As a temporary solution you can probably just tape/glue a few dupont connectors (commonly sold for example at places that sell Arduinios, Raspbery Pies and such).

 

[cj7hawk]

It's not too difficult to figure out serial async comms pinouts. A multimeter, a scope and some time is enough. Once in a while you find something weird, but generally it's not too bad.

The protocols they use? That's another matter. Hopefully it's a kind of terminal mode.

 

[g4ugm]

Very odd that one is 8-pin and one 6-pin. I guess one does in/out and one just prints. Have you tried e-mail the company as it still seems to exist?

 

[cjs]

IDC connectors for flat cables would likely not fit though, as there seems to not be enough space on the sides.

What kind of IDC connector are you thinking of? It looks to me as if 2-row .1" keyed IDC female connectors should fit just fine, since they go inside the black shroud you can see around the pins.

There were a type of connector where you crimped each wire individually, and weirdly there were no strain relief.

Sure, the standard crimp connectors that everybody calls "dupont," that come in kits like this. (I use them a lot.) The problem with them is that they're not keyed, so it's easy to insert them rotated by 180 degrees. (I suppose you could use a bit of glue or something to put a key on the connector, though.


These connectors do indeed have strain relief: it's on the pins themselves. Note that you need a particular crimper to get the strain relief to wrap properly around the insulation rather than to curl in and penetrate it, one that's "O" shaped rather than "B" shaped on the insulation part of the die. There's more information (and more pics) in this blog entry by Matt Millman. (I learned a lot about crimping from him.)

As for the pinout, the way I usually approach this is to find an obvious ground point somewhere (on the power connector, on a 7400 part, wherever) and use a continuity tester to find the grounds on the connectors. Then power it up and see if any pins on the connectors are providing power (+5 or +12 V); these are either actual power supply pins for the device at the other end or handshake signals that are active. If you see any -12 V you know you're dealing with RS-232 levels, otherwise it's TTL.

For the rest, it depends. If you can identify any of the chips on the board you can trace from the pins, often through buffers, to the chip pins and see what they are. Microcontrollers often have just a few pins that can be used with their internal UARTs. If it's all a big mystery, you probably have to figure out how to get the device to generate some serial output and use a 'scope on the various pins to figure out where it's coming out and at what rate.

 

[Bruce Tomlin]

Agree that dupont single pin cables would likely fit.

It's easy to reuse the larger dupont blocks by taking a sewing pin and use it to gently lift up the flap that holds each pin in place. Definitely worth saving up the wires from otherwise useless junk PC cases that you may encounter. Then you can take the sets of pre-assembled single dupont pin wires from amazon etc., and build a custom cable from it. I like to take the long (sticks out on both sides) header pins and use them as 0.1" gender changers to plug my re-assembled wires into solderless breadboards.

 

[MiaM]

What kind of IDC connector are you thinking of? It looks to me as if 2-row .1" keyed IDC female connectors should fit just fine, since they go inside the black shroud you can see around the pins.

The one that is used for flat cables, like for hard disks, floppies, serial/parallel/game ports and such. (I don't know if there are any 6- or 8-pin versions of such connectors, but still). They need way more space on the sides for the mechanism that locks together the different layers of the connector (at least two, one for the part with the actual sockets and such, a second that crimps and holds the crimped flat cable in place, and sometimes a third that acts as a strain relief of sorts).
Example picture (random search result, I'm using an ad blocker so sorry if it's infested with ads and whatnot, I wouldn't notice that):

Motherboard IDE Connections

IDE connectors, like floppy drive and other connectors, are keyed to ensure proper connection. Connect your IDE devices to the motherboard IDE connectors, taking care to assign these to give optimal performance for your particular system configuration. Although a single IDE channel can handle...

www.pctechguide.com

Sure, the standard crimp connectors that everybody calls "dupont," that come in kits like this. (I use them a lot.) The problem with them is that they're not keyed, so it's easy to insert them rotated by 180 degrees. (I suppose you could use a bit of glue or something to put a key on the connector, though.

This is the type of connector I'm thinking of, and I'm 100% sure that they at least used to be available with keying.

These connectors do indeed have strain relief: it's on the pins themselves. Note that you need a particular crimper to get the strain relief to wrap properly around the insulation rather than to curl in and penetrate it, one that's "O" shaped rather than "B" shaped on the insulation part of the die. There's more information (and more pics) in this blog entry by Matt Millman. (I learned a lot about crimping from him.)

Sorry if I was a bit vague, I'm referring to a strain relief intended for the outer shell of a multi wire cable, like typical round cables or for that sake custom/DIY made cable looms and such. The typical cause of grief with these connectors is when you have a shielded cable with thin inner wires that tend to break off near the crimp. I wish that the plastic shell (with space for a number of crimped pins) were available in a version with a plastic piece poking out on the cable side, with a shape suitable for for example adding a zip tie. That might had been seen as too expensive though? In particular since there is no handle and you then kind of need to either use a not-great tool (flat screw driver, channel locks or whatnot) or pull on the wires, they are prone to break.

 

[MiaM]

It's easy to reuse the larger dupont blocks by taking a sewing pin and use it to gently lift up the flap that holds each pin in place. Definitely worth saving up the wires from otherwise useless junk PC cases that you may encounter. Then you can take the sets of pre-assembled single dupont pin wires from amazon etc., and build a custom cable from it. I like to take the long (sticks out on both sides) header pins and use them as 0.1" gender changers to plug my re-assembled wires into solderless breadboards.

Where do you generally encounter the larger blocks? Single row ones with 4-5 pins are common for say PC speakers, USB connectors and such in PC cases, but IIRC I've only seen the double row ones at a job decades ago, but never really out in the wild elsewhere.

 

[cjs]

The one that is used for flat cables, like for hard disks, floppies, serial/parallel/game ports and such.

Most of those do not have latching connectors. E.g:

This is the type of connector I'm thinking of, and I'm 100% sure that they at least used to be available with keying.

Well, as I said, I buy and build a lot of these, and I've never seen one with keying. Just IDC connectors.

I'm referring to a strain relief intended for the outer shell of a multi wire cable, like typical round cables or for that sake custom/DIY made cable looms and such.

For these "dupont" pin header connectors, the shroud around the connector is not intended to provide any retaining force but merely serve as a guide so that you can't connect it with a one-pin offset in either direction. (And to key it, if using IDC connectors that have keys.)

The retaining force is provided by the female pins themselves, as you'd expect given that these are designed to be used also with unshrouded male headers, such as the COM1 and USB connections on this motherboard:



If you've got bad crimps you are probably better off pulling on the shroud to get it to "push" the female pins off the male ones, so I guess you're kind of right there, but really if there's concern about this you should not be using this type of pin header anyway.

 

[MiaM]

Most of those do not have latching connectors. E.g:

View attachment 1306121View attachment 1306122

Those cables would absolutely not fit on the type of connector this thread started with. (Of course they have too many pins, but if you just cut one so it only has 6/8 pins it would still not fit). I'm talking about the mechanism that latches the two halves of the flat cable crimp connector together.

For these "dupont" pin header connectors, the shroud around the connector is not intended to provide any retaining force but merely serve as a guide so that you can't connect it with a one-pin offset in either direction. (And to key it, if using IDC connectors that have keys.)

The retaining force is provided by the female pins themselves, as you'd expect given that these are designed to be used also with unshrouded male headers, such as the COM1 and USB connections on this motherboard:

If you've got bad crimps you are probably better off pulling on the shroud to get it to "push" the female pins off the male ones, so I guess you're kind of right there, but really if there's concern about this you should not be using this type of pin header anyway.

I'm talking about retaining the outer part of a multi wire cable to the connector. And I'm not talking about bad crimps, but rather that the individual wires are too weak to withstand disconnecting the plug by pulling the cable. In the specific case I've come across this you could argue that the shield connection should had been shorter than the thin signal wires, for the shield to act as a strain relief of sorts, but still.

Compare with the strain relief on DIN or D-SUB connectors. Those connectors would absolutely not work with thin shielded cables unless there were a strain relief.

 

[cjs]

Those cables would absolutely not fit on the type of connector this thread started with.

I do not see why not. They seem quite clearly to be 2x3 and 2x4 versions of the 2x17 shrouded header on the motherboard above, which is exactly what the floppy drive cable in the picture above fits.

I'm talking about retaining the outer part of a multi wire cable to the connector

What "outer part" are you talking about? Regardless, as I mentioned, the shroud of these connectors needs little or no force to disconnect; the connection force is provided by the pins, not the shroud.

And I'm not talking about bad crimps, but rather that the individual wires are too weak to withstand disconnecting the plug by pulling the cable.

That is the definition of a bad crimp for "dupont" connectors. A good crimp must be able to withstand the force of the wire being pulled to extract the attached pin from connection with another pin.

Compare with the strain relief on DIN or D-SUB connectors.

Those are an entirely different kind of connector. For a start, they're almost invariably soldered instead of crimped, which means the connection of wire to connector is much weaker. If you're going to solder things, yes, you will need a separate strain relief because you should never apply mechanical force to soldered connections.

 

[MiaM]

I do not see why not. They seem quite clearly to be 2x3 and 2x4 versions of the 2x17 shrouded header on the motherboard above, which is exactly what the floppy drive cable in the picture above fits.


What "outer part" are you talking about? Regardless, as I mentioned, the shroud of these connectors needs little or no force to disconnect; the connection force is provided by the pins, not the shroud.

Look again at the sides. On the thread start picture, the space between the pins and the shroud/edge is about one pin space (2.54mm / 1/10"), while on the picture of a PC motherboard you show the space between pin 1/2/39/40 and the shroud is about 1½ pin space. The type of connector on the IDE/floppy style flat cables would absolutely not fit in the connector type in the thread start.

That is the definition of a bad crimp for "dupont" connectors. A good crimp must be able to withstand the force of the wire being pulled to extract the attached pin from connection with another pin.

No, the strands from the crimped wire would stay in place, while the wire would break apart next to the crimp, due to the wires being too thing to withstand the force when pulling out the plug by pulling on the cable rather than on the connector (that lacks any handle to pull on).

Those are an entirely different kind of connector. For a start, they're almost invariably soldered instead of crimped, which means the connection of wire to connector is much weaker. If you're going to solder things, yes, you will need a separate strain relief because you should never apply mechanical force to soldered connections.

Both can be used, and have been used, with cables where the individual wires are too weak without a strain relief on the outer sleeve of the cable.
I don't know if this is a regional difference on what cables were commonly available? Shielded cable sold on spools, intended for for example RCA/DIN connectors, used to have very thin inner wires here in Sweden. I don't know what gauges / square areas were common elsewhere. I've noticed that it seems like whenever I cut a pre made RCA cable the inner wires seems thicker than this, so it might had been a regional thing.

The point is that it would be useful if the shell of these connectors would have a strain relief to attach the outer sleve of multi wire cables, to protect the individual wires from breaking off.

 

[cjs]

On the thread start picture, the space between the pins and the shroud/edge is about one pin space (2.54mm / 1/10"), while on the picture of a PC motherboard you show the space between pin 1/2/39/40 and the shroud is about 1½ pin space.

Ah, I see. Yes, you're right; the IDC connectors will not work. I've never actually seen shrouded .1" connectors like that. I guess they're doing some interesting custom thing.

No, the strands from the crimped wire would stay in place, while the wire would break apart next to the crimp, due to the wires being too thing to withstand the force when pulling out the plug by pulling on the cable rather than on the connector....

First, there are two crimps there: one on the wire strands and one on the insulation. You can't pull on the wire strands themselves unless you strip off all the insulation first. So if you pull on the wire, you will be pulling against mainly the insulation crimp, with possibly some tension on the wire crimp. But if you can pull the insulation to break the insulation crimp, the connector is not properly crimped. (This is a standard test after doing a crimp: give the wire a good hard tug to make sure it doesn't separate from the connector.)

Both can be used, and have been used, with cables where the individual wires are too weak without a strain relief on the outer sleeve of the cable.

I don't know if the wires within the cable are too weak or not, but it doesn't matter, because a solder connection is far weaker. As I said, you cannot put mechanical strain on solder connections. So any connector using solder connections has to have a separate strain relief. But these .1" connectors are crimped, not soldered.

The point is that it would be useful if the shell of these connectors would have a strain relief to attach the outer sleve of multi wire cables, to protect the individual wires from breaking off.

This is simply not the design; you are confusing what one must do for soldered connections with what one might optionally do with crimped connections. But it remains: if you pull on a crimped wire and it separates from the pin, the crimp was bad. There is a reason that these systems do two crimps, one for the wire itself and one for the insulation.

 

[MiaM]

Well, the insulation on these wires are also very weak. Think like the inner wires in the worst RJ11 cables, but worse.

 

[cjs]

Well, the insulation on these wires are also very weak. Think like the inner wires in the worst RJ11 cables, but worse.

Not the wire I use. If someone's using terrible wire there's really not much you can do about that; they could just as well use a cable with outer sheathing that will break instead of pulling on the connector strain relief.

Basically, it sounds as if you just don't like the "dupont" connector design because it doesn't satisfy needs that you have that others don't. If the connector isn't working for you, just choose another connector rather than going on about how a connector that's fine for certain designs needs to be changed for yours because you don't want to use a better connector for your purposes.

 

[MiaM]

This was the only type of wire available back in the days from the major electronics component suppliers and also consumer electronics shop accessory suppliers, unless you went with some sort of "pro" wire meant for industrial or pro audio use.

 

[cj7hawk]

@MiaM is correct - The strain relief on the crimps is not that great, and I have similar issues - even when using quality silicon wire. Usually you *can* pull the plug out by the wire, but the shroud is intended to take the force and will ensure the wire isn't damaged with repeated inserts and removals. Not to mention dupont style connectors are typically used with ribbon cable wire - a very high plasticized wire insulator.

The power plug visible is probably a 2.5mm center pin, which would suggest the pins are about 0.15" but it could also be a 2mm center pin, so it's hard to tell. I don't think they are 0.2" but it's also possible.

Unless the OP comes back, and confirms, then it's difficult to know what the best solution is.

Once you get above 0.1" spacing, it becomes practical to use 3D printed housings for plugs. Sometimes you can get away with dupont style terminators even with larger pins - I've used then with a 3D printed plug before to make a power supply plug for the Sinclair QL - which worked better than I expected.

There are also larger pins you can choose from different plugs and, again, rehouse the pins in a 3D printed shell.

Generally you can't print latches on something that fine, but you can make sure to get a good friction fit on the plugs in most cases, and enough friction on the plug to receptacle surface to stop the plugs coming out and sometimes print interference latches that will significantly increase the force needed to insert/remove the plug.

 

[cjs]

This was the only type of wire available back in the days from the major electronics component suppliers and also consumer electronics shop accessory suppliers, unless you went with some sort of "pro" wire meant for industrial or pro audio use.

This is simply false. I use cheap AliExpress 24 AWG wire in my connections, and I test every single one I crimp with a force greatly exceeding the disconnect force, and I've never seen the insulation fail. Not once. (If they fail the test, it's invariably due to a bad crimp.)

Are you telling me that today's cheap wire from AliExpress is somehow of vastly higher quality than the high quality stuff "back in the days"?