Serial ports on a Plus

[gdhgdh]

Hi

I have a Plus and external SCSI box that started to take notice of recently. The Plus now has 4MB of RAM and a working system disk with 6.1.8, courtesy of Basilisk and a PCI SCSI card on my Linux box.

I'm now taking the next steps of MacTCP + PPP, but I have run up against problems with the serial ports.

I bought http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=140163948672

but even at 9600/8N1 with no XON or RTS handshaking, I can get no data in or out of ZTerm 0.9 with either modem or null modem cables.

In fact, I even tried just putting a bit of wire between pins 2 and 3 of the RS232 connector but got no echo. Same thing happens with both the Modem and Printer ports (AppleTalk is off - ZTerm let me select the Printer Port without complaint)

Is the serial logic likely to be fried on the board or is there something else I can try? SCSI, floppy, keyboard, mouse, sound and screen on the machine all work perfectly.

Cheers,

Gavin.

 

[equill]

The secret may lie in the seller's disclaimer:

'Please note that attaching a PC Serial 9D device to a Mac computer via this adapter provides no guarantee that the device will provide complete functionality - or actually even work at all. Using this adapter as a part of PC / Mac Data Transfer solution will generally prove more successful (additional software may be required).'

You need a DB-9M/MiniDIN-8M cable or adapter made for Macintosh. They are no longer common, but I bought a couple from the French eBay seller salut59 last year.

http://pinouts.ws/db9-rs232-pinout.html

http://www.interfacebus.com/Apple_RS232_DB9_Pinout.html

de

 

[Mac128]

Yes, equal is correct I have several of these adapters I use with AppleTalk and they work flawlessly, however, they do not work with any modems I have tried, which otherwise work well with the dedicated modem cable. With the pin-out information, you should be able to construct your own. SOme of these links may help too:

http://docs.info.apple.com/article.html?artnum=170

http://docs.info.apple.com/article.html?artnum=1762

http://docs.info.apple.com/article.html?artnum=12943

http://docs.info.apple.com/article.html?artnum=1780

http://docs.info.apple.com/article.html?artnum=7757

 

[Charlieman]

I think that gdhgdh would be better off making his own cable. I've done it several times for Mac modems and find it a quicker solution than struggling to use a sealed adapter/cable with no pinout information for the product.

Tip: when soldering a mini DIN connector, plug it into a potato to act as a heat sink. It reduces the chance of overcooking the plastic that locates the connector pins.

 

[gdhgdh]

Thanks for the info. I can't believe that the adapter would be wired incorrectly, but I'll give it a shot.

Cheers,

Gavin.

 

[Mac128]

gdhgdh, perhaps I was a bit short in my explanation ... did the adapters come with any sort of packaging specifying modem use? Unfortunately for cables, if it looks like a duck and walks like a duck, brother it isn't always a duck. Like cables the adapters can be specific for printing, or for modem, or even wired straight through for use with whatever type of cable you have.

What I and others are saying is that the problem most likely lies with the cable you are using with your modem. A standard PC/serial cable will not work work, even on a PC. You still need a special modem cable. A standard data/printer cable will not work. Assuming you are using a PC/Serial modem cable known to work on a PC, then you have the added problem that the adapter you bought is designed for data transfer, which uses different pins than for a modem. Mac to Serial adapters are usually customized application, so it is unlikely your adapter is simply wired straight through, but rather designed to adapt the Mac's non-standard serial port for a specific PC serial use.