On Wed, 16 Jul 2003, Larson, Timothy E. wrote:

> Henry:
> >Most (all?) LaserWriter's will speak serial instead of LocalTalk if
> >you connect a serial cable instead of a LocalTalk dongle to them.
>
> How do I know which is which?
> Don't the cables look the same?

No. Localtalk cables have only 3 pins; they will not connect to the serial
ports. The Localtalk interface will connect, but that's not the localtalk
cable.

> Bill:
> >Check the owner's manual. Some supported it, some did not.
>
> Unfortunately I'm not the original owner.
> I don't have it.
> Maybe it is online though?

Maybe.

> John:
> >Find the documentation for your printer and see if it will allow non-Mac
> >printers to connect to it via an RS-232 to Apple serial cable. If so, you
> >should be able to initialise the port in NetBSD by updating /etc/ttys, and
> >you may see something (flashing light, maybe even a page) by just catting
> >a PostScript file to that serial port.
>
> You meant "non-Mac computers to connect" right?
> All I have is Macs, though they all run BSD or Linux now.  :)
> I might have a couple DB25 serial to Apple serial cables, though.

Note: You'll need a null-modem setup. Either a Mac-PC laplink cable, or a
Mac-Modem+NullModem+Modem-PC cable combo.

> I didn't know what they were good for, before, but I think I am
> understanding now.

> So if I can find documentation (as I mentioned, I don't have any)
> about connecting a PC to the 4/600 with one of these cables, that
> would prove that the 4/600 can speak serial, right?

Yep.

> >Note that most direct computer to printer connections are capable of both
> >serial and LocalTalk, but I'm not sure if the printer will listen to
> >serial if a LocalTalk connection is sensed. You may need to make your own
> >cable which looks to the printer like a regular serial connection. This
> >involves converting the connection from balanced RS-422 to single ended
> >RS-232 by letting TxD+ float and tying RxD+ to ground on both sides.
>
> So, Apple's DIN8 ports may be able to function as both RS422 and RS232
> depending on what kind of cable I use?

No. Apple DIN8 ports are RS-422.

You can, though, wire a passive cable to translate. That's how all Mac
modem cables work.

The difference is that the Apple port didn't change, the cable did
translation.

> (I would think the cables could be identical, with only the ports
> built differently.  *shrug*)

> That seems to be what Henry is saying above, too, and I found a page
> at free.fr that also backs that up.

> I'm sure I have several of these cables around.  Is there any way to
> tell which way they are wired, without performing surgery on them?

If it has a mini-DIN8 and is not a LocalTalk interface, it's RS-422 for a
Mac (assuming you have no Sparc cables around; they used mini-DIN8s too,
but differently). If it has a DB-9 or DB-25, it's RS-232.

> >So if you can't just send serial data from NetBSD, and you don't want to
> >make a cable, you can get an Ethernet to LocalTalk bridge (they work very
> >well; I'm using one), or you can get something like an LC (II, III) or
> >Quadra 605 as they are small and take very little power, and install the
> >free LocalTalk LaserWriter Bridge software from Apple.
>
> That's what I'm trying to avoid.
> I figured my SE/30 was small and quiet enough, and could serve other purposes as well since it would be on 24/7.
> I'm going to be bummed if I've decked out this SE/30 only to discover it can't meet my primary goal.

Take care,

Bill