how to convert a serial cable to a 36-pin centronics cable

[wossname]

Does anyone know if there are any adaptors available to solve my problem...

I have a Palm top computer that uses a normal 9-pin serial cable (with female plug). I also have a standard dot matrix printer with a standard 36 pin centronics port on it.

I want to send data from my palm top computer to the printer using the above resources, except I don't have an adaptor to enable me to link the two devices together. (i dont even know itf its possible!).

does anyone know of an adaptor that can do this? Or do you have a circuit diagram that will enable me to build my own (i dont know what the pin-mapping should look like).

Sorry about posting this in the math forum, but I figured this would be the place with the most technically minded genii!

Please help.

Adam.

[Destined Soul]

I'm sure there's a couple of adapters out there that should do this. I do remember seeing one that went from a serial port to something bigger, but I can't remember what size it was. (Thought it might be a parallel connector.)

Try checking out a local hardware parts store. If they don't have a specific adapter, you should be able to do it with 2 or 3 adapters.

However, if I can ask one question: Does this palm top have its own built in printing software? If it doesn't, you'll have to download some or program it yourself. ;)

You could also build a program yourself, but you'll need the hardware specs for the intput and output signals for both devices. I have no idea how easy/hard printer code is to make, so I can't' really suggest much there.

On a side note, you'll probably have to get the parts from a store that most likely has the pre-made adapter. If they don't, they should at least know where to look for one.

Hope this helps, and best of luck on your searching.

PS: (something for the math forum) 1+1 = 3, but only for large enough values of 1.

Destined.

[wossname]

I did intend to program my own 'printer driver' program but nothing so fancy as actual formatted output. Just plain text, so I could print out the memo files on it without having to mess around with switching on my PC and all that just for the sake of a paragraph or two!

I went to another store today and they thought it was a weird thing to want to convert 9 pin to 36 pin. Doesnt seem so odd to me, serial is very common and so is 36 pin centronics, so whats wrong with wanting to interface the 2?

I have already got a serial to parallel (25 pin) adaptor, which i tried in conjunction with a standard 2 way printer cable but not a single byte of data would reach the printer.

I really need a special adaptor for this or failing that a circuit diagram so i can make one myself.

Does anyone know a good place to find circuit diagrams?

[Destined Soul]

Interesting. I haven't tried programming for a palm top, so I'm not sure how your code (I'm assuming you have some basic code written) is outputing to the printer.

I've done a little bit of programming using analog-to-digital boards and the like, and I'm wondering how you're sending the data out? Normally, my code was at such a low level, I'd actually have to specify the hex address of the output device I was using and a specific pin to send the signal(s) out on. If you manually declare which pins to use, then it may be possible it's not reaching the proper pin on the printer. (And hence, probably why you want a circuit diagram.)

Have you tried looking up the schematic diagram for the pin assignments for your printer (and palm top)? That would be my starting point.

How did you manage to connect a 25 pin connector to your 36 pin printer? Was it another adapter And was the program you used calling a generic printfile(file) type function, or is it completely "homemade"?

Hopefully you can figure it out, though.

Destined

[wossname]

i managed to connect a 25 pin to a 36 pin using a normal printer cable. Nothing special there!

The program doing the 'talking' isn't at fault, i can use it to communicate directly with my old atari ST computer through its modem port.

somehow i need to get an adaptor that will properly convert 9 pin serial to 36 pin centronics untimately, i suppose the printer cable is an uneccesary step...


{Palm device} -------> {serial cable} ---------> {Adaptor} --> {Printer}

[fbokker]

There is no way to just connect the right pins with each other. Serial and parallel (which includes also the centronics ports of the printer) are totally different concepts of data transmission. While serial ports transmit bitwise through 1 line, the parallel port has 8 data channels, which transmit simultaneously to make up 8 bits. I do not think that there are ready-made adapters!* If you really want to do this, it'll get ´lots of work and you need electronics skills.
If you have a palmtop, what about IRDA transmission?

*hmm, just found one, but it is not a real adapter, more kind of a translator. check out:

http://stores.yahoo.com/secureswitch/sertoparcon.html

[wossname]

Thats what I feared, I guess i already knew it, but i was clinging on to some hope that I may be able to bodge something together.

I have looked into IRDA transmission but I'd need either a new printer or some sort of IR reciever that will plug into the printer port. Hold on though, doesn't the IR port use the same serial technology as the serial port itself?

Yesterday I came up with a program for my Atari ST computer to act as an interface between the Palm and the printer, it works with small memos but I have to keep splitting them up into chunks of 255 bytes to get the data through. Large messages get all mashed up and garbled!

I just (finally) got my hands on a C compiler for the atari which should make the interface easier to do.

[fbokker]

yes, IRDA is also kind of serial communication. But if your printer supports it, it would not be your concern. The same would apply, if your printer accidentially also had a serial port.
Together with the atari as interface (weird idea!) it should be no problem to write something. But where is the need for that? I guess, you have some software like PalmDesktop to synchronize your palmtop. Then you can just print it from your normal computer.

[wossname]

Because that would be admitting defeat! :))

I'm just being awkward really, the atari is just sitting there doing nothing, so i thought I'd put it to some use as an interface.

It's not easy getting these two technologies to talk to each other and what makes it worse is that I'm using C on the palm top and Basic on the atari!!!

I just saw a serial to centronics converter, which costs a fortune!

That C compiler i got yesterday is rubbish, no port support at all!

Such is life.