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SE/30 to modern Mac via serial cable

megabyte

Well-known member
Hi all.

I try to connect SE/30 and iMac 2017 via serial connection using next components:

- mini DIN 8 to DB25 mac modem cable (bought on ebay)
- DB25-DB9 converter
- DB9-USB serial controller

At SE/30 side I tried to use ZTerm with different speeds (19.2-115.2).
At Mac side I tried a lot of serial terminal software (minicom, Serial, hyperterminal+virtualbox etc.)

Both computers has XON/XOFF handshaking turned on.

Both computers transmit characters without any problem. But when I tried to send file via ZMODEM I always has a CRC-error on SE/30 side. I tried to use all options of ZMODEM settings (window size, special characters filtering etc), but got no result.

It seems to me that transferring files through the terminal should not be so difficult. What am I doing wrong?
 

ironborn65

Well-known member
this is of interest to me as well, since I have a similar arrangement.
On the modern side I have a Bigsur an a MacBook Air Silicon, on the legacy a Mac Classic.
I can transmit characters using ZTerm/Classic across any terminal software on the modern Mac but sending files fails to me because I did not find any ZMODEM capable software on the modern mac, so the protocol is not implemented on one end.
So I tried to use BasiliskII in the Mac to take advantage ZTerm, but despite many attempts Basilisk does not see the virtual serial port.
I was inspired by this https://www.savagetaylor.com/2020/1...transfer-from-basilisk-ii-to-a-68k-macintosh/

I hope this might somehow help
 

Byte Knight

Well-known member
Hi all.

I try to connect SE/30 and iMac 2017 via serial connection using next components:

- mini DIN 8 to DB25 mac modem cable (bought on ebay)
- DB25-DB9 converter
- DB9-USB serial controller

At SE/30 side I tried to use ZTerm with different speeds (19.2-115.2).
At Mac side I tried a lot of serial terminal software (minicom, Serial, hyperterminal+virtualbox etc.)

Both computers has XON/XOFF handshaking turned on.

Both computers transmit characters without any problem. But when I tried to send file via ZMODEM I always has a CRC-error on SE/30 side. I tried to use all options of ZMODEM settings (window size, special characters filtering etc), but got no result.

It seems to me that transferring files through the terminal should not be so difficult. What am I doing wrong?

Try Zoc terminal program on the iMac side - it's the best modern terminal program out there: https://www.emtec.com/zoc/

You could also try YMODEM or XMODEM protocols .
 

4seasonphoto

Well-known member
Both computers transmit characters without any problem. But when I tried to send file via ZMODEM I always has a CRC-error on SE/30 side. I tried to use all options of ZMODEM settings (window size, special characters filtering etc), but got no result.

It seems to me that transferring files through the terminal should not be so difficult. What am I doing wrong?
This sounds really familiar, and I think your problem is maybe with the Mini DIN-8 -> DB25 cable. When higher speed modems became popular, a revised Mini DIN-8 - DB25 cable with support for hardware handshaking became necessary, but even in the 1990s, there were lots of the older-style cables still in circulation, and there's usually no way to tell what you've got without checking with a multimeter. You can often reuse the existing cable by cutting off the DB25 end and reconfiguring (assuming the DIN-8 side has all pins connected, which IME it usually does). Here's how a proper cable should be configured:
https://kb.iu.edu/d/achi
I seem to vaguely recall that unless this was done, you could send strings of characters between computers, but file transfers would fail, exactly as you describe.
 

4seasonphoto

Well-known member
shouldn't it be a null-modem/cross cable?
Yes, but if you can type characters from one machine to the other, then something is already acting as null modem adapter because if that weren't the case, you wouldn't be able to send even that across.

Also, IIRC standard ImageWriter II mini DIN-8 cables are already wired as null-modem.
 
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