OS X 10.6 + Airport Express + Keyspan USB to serial adapter = Imagewriter?

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Level 10

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OS X 10.6 + Airport Express + Keyspan USB to serial adapter = Imagewriter?

At present I'm enjoying success printing to my ancient Localtalk-equipped Apple Imagewriter II from all the OS X Tiger machines in Galt's Gulch. The Imagewriter, along with my HP LaserJet 4MP are connected to my Airport network via an AsanteTalk Ethernet to Localtalk bridge, and my computers are happy with the Imagewriter driver available from the Linux Foundation.

Encouraged by my recent success using the HP LaserJet with this USB to parallel adapter connected to an Airport Express, I'm wondering if I could use this Keyspan USB to serial adapter in conjunction with another Airport Express to print to the Imagewriter. When I upgrade to Snow Leopard, I would like the Imagewriter to be available to all my computers on the network as it is now.

Everything I've read so far would indicate the adapter should work fine connected directly to a computer, but I'm not sure about the Express. I would not waste time posting a question in the Airport forum since most people have no idea what an Imagewriter is. The few who read this forum will know.

Quoting from the Linux Foundation's website:

The current ImageWriter driver supports printing via AppleTalk to an AppleTalk-enabled ImageWriter II or ImageWriter LQ, and printing via a supported serial port to all three models of Apple ImageWriter.

Of course I know Appletalk is no longer supported. I would expect to remove the LocalTalk option card from the printer, and revert to its original serial-only configuration.

I know I could use an iMac to share the printer, but I don't consider that a practical option.

So has anyone tried a USB to serial adapter on the Express?

Powerbooks  iMacs  iPods  Airports  Appletalk printers , Mac OS X (10.4.11),  25 years Apple!  "alittle" is not a word  neither is "alot"

Posted on Apr 12, 2010 7:47 PM

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Answer 1

adsfushi72

Level 4

1,115 points

Apr 15, 2010 1:40 PM in response to John Galt

I tried the setup you're describing, and it doesn't seem to work. Here are the details (in case I'm forgetting something important):
I connected my non-Appletalk ImageWriter II to a USB/serial adapter (I'm not sure of what brand). I connected the adapter to an Express on my network. Then I turned on the ImageWriter and made sure the "Select" light was on. Finally, I opened AirPort Utility and went to the printer configuration pane for the Express. No printers appeared in the list.
When I get the chance, I'll try connecting a newer serial printer in order to determine whether it's the adapter or the printer the AirPort doesn't like.

Message was edited by: adsfushi72

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Answer 2

John Galt Author

Level 10

146,516 points

Apr 15, 2010 4:04 PM in response to adsfushi72

Thanks for the report, adsfushi72.

The Keyspan adapter seems to be the only one people have reported the slightest bit of success with, so I'd be reluctant to try anything else. USB-parallel adapters have trouble as well. I believe there are only two brands known to work.

I may risk the $30 to find out. A direct connection to the computer would be acceptable, though reluctantly. I generally use the Imagewriter from only one computer.

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Answer 3

John Galt Author

Level 10

146,516 points

Apr 25, 2010 8:42 PM in response to John Galt

Well, I got a Keyspan USA-19HS adapter, but it appears I'll need another cable adapter before I can even get started. Some questions while I wait:

• The Keyspan's DB-9 connector has male signal pins, but female hardware, which seems strange. I ordered a DB-9 m/f extension that appears to have compatible hardware, and I have an original mini-din 8 to DB-9 female that I used with my old SE/30. Does anyone know if the Imagewriter will need a swap a/k/a "null modem" cable with the Keyspan?
• Rather than unplug the Appletalk option board, I simply opened DIP switch SW2-4. It's not necessary to remove the Localtalk option board to enable the Imagewriter's serial port, is it?
• Has anyone made this work? Google doesn't show many hits.

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Answer 4

John Galt Author

Level 10

146,516 points

May 11, 2010 12:09 PM in response to John Galt

One step forward...

It was necessary to run the Linux Printing Foomatic driver installer *while the Keyspan is connected*; this is critical for the driver to recognize the printer. The Imagewriter II and Keyspan drivers then appeared in Printer Setup Utility. Good so far!

Problem is, performing a print job goes nowhere:

It says "printing" but it's not.

To connect the Keyspan to the Imagewriter I am using a null modem (swap) cable and the DB-9 to mini din 8 adapter that I used with my original Mac Plus (I think). I also tried a straight DB-9 cable with the correct hardware, but the print dialog says the printer is busy, "will try again in 30 seconds", so I have reason to expect the Keyspan is talking to the Imagewriter when using the swap cable - I don't know if the DB-9 to mini din 8 cable swaps pins 2 and 3 or not, hence the reason for trying the null modem cable as well as a "straight" one.

I have not yet removed the Appletalk card from the Imagewriter; I just opened SW2-4, so perhaps the card really has to be removed...? I'll do that as soon as I remember how it went in to begin with.

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Answer 5

May 11, 2010 3:58 PM in response to John Galt

You should have your speed set to 8-one-noparity 9600 unless you changed the switches. You should not have to remove the card, but the cable is not trivial.

Both your computer port and the ImageWriter are likely to be DTE. \[Mini DIN-8 is always DTE.] So an odd number of crossovers would normally be needed.

The drivers/receivers are RS422/3 (dual-rail with + and - for each signal. To convert to RS232, you open + on the Driver, ground + on the Receiver.

What does the USB adapter present, DB25 or DB9? I have some wiring diagrams penciled into my book on page 89, and a note that the pin numbers shown in C-1 on page 88 are mirror-image of reality.

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Answer 6

John Galt Author

Level 10

146,516 points

May 11, 2010 5:08 PM in response to Grant Bennet-Alder

The Keyspan presents DB-9 male connector pins, but it has female hardware (nuts) which I thought confusing.

For the Imagewriter, the only mini-din 8 adapter I have terminates with a DB-9 female connector which also has nuts. I thought I used this with my original Mac Plus and Imagewriter, but I could be wrong - it has an Apple logo on it, but it might have been for a modem. Since this adapter also has female hardware (nuts), I can't just connect the two directly, but I took this as a hint that I shouldn't just file off the offending hardware :-/

I got around that problem by purchasing a DB-9 m/f cable, so now all the attaching hardware matches - both ends of this cable are equipped with screws. Since I don't know if the DB-9 to mini-din 8 adapter was intended for a modem or a printer, I also purchased a DB-9 m/f "null modem" cable, what I call a crossover, so I could try both.

You should have your speed set to 8-one-noparity 9600 unless you changed the switches.

I haven't changed the DIP switches - they're still set 9600, 8-1-N. I would have thought the Keyspan would have some provision for setting its serial port baud rate, but there doesn't appear to be any way to do that... I'm basically going off of the Linux Foundation's general recommendation to use the Keyspan adapter, but without additional documentation it's difficult for me to determine exactly how everything is supposed to work.

I tried removing the card, it makes no difference 😟

What book are you referring to? Fortunately I have the Imagewriter II manual, with a pretty good pinout diagram. I was hoping not to have to get that involved, especially since I don't know what pins the Keyspan its using for its signals. It has no separate power supply and I believe a USB port only supplies +5v so it's probably not truly RS-422/3.

I was hoping someone would say "buy this cable from Amazon" but I guess I'll have to get my hands dirty (sigh).

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Answer 7

May 11, 2010 5:37 PM in response to John Galt

The info I penciled into my ImageWriter II Owner's manual comes from Inside Macintosh, Volume III p24 for the DB-9 and Volume IV p248 for the DIN-9:

1 Ground
2 +5 Volts (from the Mac 128K, 512K)
3 Ground
4 TxData +
5 TxData -
6 +12 Volts (from the Mac 128K, 512K)
7 Handshake/ ext Clock (INPUT to mac 128K, 512K)
8 RxData +
9 RxData -

1 Output Handshake
2 Input Handshake/Ext Clock
3 TxData -
4 Ground
5 RxData -
6 TxData +
7 n.c.
8 RxData +

On the Mini DIN8, Inside Macintosh shows pins 3 and 4 close, pin 5 far away. As I said above, the pinout on page 88 of the ImageWriter II manual is the mirror image of reality.

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Answer 8

John Galt Author

Level 10

146,516 points

May 11, 2010 6:35 PM in response to Grant Bennet-Alder

Thank you Grant, that pinout matches what I have in the Imagewriter II manual. It is indeed a mirror image of the printer's socket, or I can think of it as a picture of the cable end.

Apparently Apple doesn't use pins 2 and 3 for Tx and Rx...! But then again it's RS-422/423. As far as I know there is no standard DB-9 pinout for that, so all bets are off.

Obviously this presents a fundamental problem. I would imagine the Keyspan is using standard RS-232 pinout designations, and if that's the case those signals aren't going anywhere with what I've patched together, null modem or not. At least it explains things.

Sure wish I could find that magic cable... Oh well, it's just tedium to sort them all out.

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Answer 9

May 12, 2010 11:07 AM in response to John Galt

If you were connecting a Mac 128K or 512K, the cable you need is pictured at the top of page 27 or the ImageWriter manual, and is number M0185. There was also a very short pigtail cable available, possibly M0197.

Instead, you need to design a crossover cable that connects:

RS232...RS422/3
TxD ..... 5 RxD -
gnd ..... 8 RxD + ("Ground + on Receiver")
RxD ..... 3 TxD -
n.c. ...... 6 TxD + ("Open + on Driver")
DSR ..... 1 DTR
DTR ..... 2 DSR
gnd ..... 4 gnd
n.c. ..... 7 n.c.

You can buy a replacement DB-9 at Radio Shack and other outlets. To replace the Mini DIN8, forgetaboutit.

Caution: It is very tempting to look at the diagram of the DIN8 pins and say "Oh this is the socket rather than the plug." The problem with that diagram is that it is neither -- the pin numbers are WRONG. Pins 3 and 4 are close together. Pin 5 is farther away. That is neither the plug nor the jack, it is a mistake. This also means that pins 1 and 2 are reversed, and pins 6 and 8 are reversed.

Message was edited by: Grant Bennet-Alder

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Answer 10

John Galt Author

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146,516 points

May 12, 2010 7:11 PM in response to Grant Bennet-Alder

That's great information Grant, thank you.

My first challenge is to identify the Keyspan's DB-9 pinouts, which I imagine ought to be either RS-232 DTE or DSE but conventional nonetheless. I emailed Keyspan/Tripp-Lite tech support with that question but I'm not holding my breath waiting for an answer.

Caution: It is very tempting to look at the diagram of the DIN8 pins and say "Oh this is the socket rather than the plug." ... the pin numbers are WRONG.

That's exactly what I did! You can imagine the aggravation you just saved me with this clarification.

Rather than build a converter cable as you suggest, I think the simplest solution is to design a DB-9 to mini-din 8 cable using the correct signals. Mini-din 8-pin connectors are actually easily found on eBay, but I have lots of Localtalk cables and PhoneNet adapters I can sacrifice. I also have some DB-9 hardware so it will all look nice (eventually).

This ought to be enough information to cobble a cable together. I'll use your connection diagram - I was about to work on that last night but you've already done the work for me 🙂

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Answer 11

John Galt Author

Level 10

146,516 points

May 12, 2010 7:35 PM in response to Grant Bennet-Alder

Just to be sure Grant... here is the picture from my Imagewriter II user's manual, Appendix D, page 126:

Are the pins in this figure numbered correctly, or not?

Here is the entire page (too big to fit nicely on the discussions board). To your knowledge, are tables D-4 and D-5 accurate?

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Answer 12

Jan Hedlund

Level 7

23,419 points

May 12, 2010 11:19 PM in response to John Galt

Hi John,

My first challenge is to identify the Keyspan's DB-9 pinouts

I do not know whether it is for the exact adapter model in question, but would the list at "KEYSPAN DB9 PINOUT" in this web page be what you are looking for?

The Keyspan presents DB-9 male connector pins, but it has female hardware (nuts) which I thought confusing.

A normal serial port on a PC is arranged like that.

I think the simplest solution is to design a DB-9 to mini-din 8 cable

Since there is limited space inside MiniDIN connectors, it may be easier (if possible) to keep that side intact with the cable, and then do the soldering on the DB-9 side. For experiments, you may even want to cut cables from both sides, and then use a simple cross-connection box in between.

Jan

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Answer 13

John Galt Author

Level 10

146,516 points

May 13, 2010 9:00 AM in response to Jan Hedlund

Thanks for the link Jan!

Apparently Tripp-Lite's site uses cookies for navigation (arrgh!!!), so it wasn't as easy as following the link, which just took me to the product's main page. Another case of page designers showing off their cleverness.

I had looked for a pinout before but couldn't find one, but knowing you found it I eventually did too:

So... if the Imagewriter II manual's Figure D-1 and Table D-4 above are each correct, I believe this is how I should construct my cable:

mini-8 ... Keyspan DB-9 1 DTR ... 1 DCD, 6 DSR, 8 CTS (jumpered together at DB-9) 2 DSR ... 4 DTR 3 Tx- ... 2 RX (or just leave it open) 4 SG ... 5 GND 5 Rx- ... 3 TX 6 Tx+ ... (open) 7 (open) ... (open) 8 Rx+, 4 SG (jumpered together at mini-8) ... (open) (not implemented) ... 7 RTS (open) (not implemented) ... 9 RI (open)
What do you think?

A normal serial port on a PC is arranged like that.

That explains it. Nothing's "normal" about a PC, as far as I'm concerned.
🙂

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Answer 14

May 13, 2010 9:26 AM in response to Jan Hedlund

on the Mini DIN8 connector, pins 3 and 4 are close together, regardless of whether you are looking at the plug or the jack. Pins 1 3 and 6 are to the same side, pins 2 5 and 8 are toward the other side. This is based on the information from Inside Macintosh, which has been read many more times than the ImageWriter II manual, and has had ample opportunity for revision.

At first it seems possible that the ImageWriter connector pin numbering could differ from the Mac, but that would be truly bizarre. The effect of that pin number reversal would effect an additional crossover -- how odd.

You do want to ground DIN8 pin 8, not leave it open -- from which side of the cable does not matter.

Your ImageWriter manual has different page numbering and different Appendix numbering than mine. My C-5 shows a cross cable for DB-25, and I have no additional diagrams in that section.

Message was edited by: Grant Bennet-Alder

Message was edited by: Grant Bennet-Alder

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Answer 15

John Galt Author

Level 10

146,516 points

May 13, 2010 9:28 AM in response to Grant Bennet-Alder

Thank you Grant... as I understand it, I should consider the pin diagram incorrect and "reverse" pins 1 & 2, 3 & 5, 6 & 8 from what's shown in the above Figure D-1. Correct?

According to Inside Macintosh (which I don't have), are the pin designations in Table D-4 correct, notwithstanding the incorrect Figure D-1 (in other words, does the table reference the "correct" pins)?

You do want to ground DIN8 pin 8, not leave it open -- from which side of the cable does not matter.

Thanks for the clarification, I believe the intent is to prevent the Imagewriter from receiving random data, correct?

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