View Full Version : Null modem for the C64?

July 20th, 2003, 03:25 PM
Has anyone ever made a null modem and know the programming that goes with it? I might be getting a second one.


July 20th, 2003, 09:20 PM
Has anyone ever made a null modem and know the programming that goes with it? I might be getting a second one.


I don't know if this will help for a C64, but for a standard RS-232 port, a null modem cable has connections from pin 2 on each to pin 3 on the other, then pin 7 to pin 7.

July 21st, 2003, 12:14 AM
Here is the pinout for the C64's serial port. I am not sure what to connect to what, don't know the terms very well. I have a direct connect setup now, between 2 pc's and know the PC pinout, the C64 is a different animal though.

Go see that page, there's LOTS more than just for the Commodore.


July 21st, 2003, 09:32 PM
Okay, in different words:

Data out from each end goes to Data in on the other end. Then connect ground to ground.

August 1st, 2003, 09:21 PM
Warning the Commodore 64 does not have a complete RS-232 circuit, it has a lot of it but the voltages are not RS-232 standard. There are several interfaces on the net that help get the 64 up to RS-232 standard.

The only two other computers I know of that one coud relatively safely hook to a 64 without special circuits are another Commodore 64/128/VIC/Plus/4 and a Mac with the RS-422 serial port.

As far as using null modems get a nice terminal like Novaterm that supports a lot of U/D protocols and set them (the two computers) to half duplex (also called local echo). Once you can type on each keyboard and see it on the other you will be able to transfer.

Also without a special expansion port serial interface (like Turbo232 or Swiftlink) the Commodore 64 is limited in speed via it's built-in RS-232 (part due to the 1mhz processor and also depending on the programming of the terminal used) usually it's 2400 baud (4800 on supersnapshot's snapterm).

August 2nd, 2003, 05:58 AM
Thanks for the links, joecommodore!
I don't want to adapt to rs232, just some c64's and my classic macs. I figure why not. What I am interested in is getting TFE's (the final ethernet) adapters for the c64's and some version of the same board for the mac's serial port and have them all properly networked (if software is available for that kind of thing) and on a server(my main pc). If the tfe's can be priced less than say, $30-40 US, then I will get some of them.


When I finally get a ps for this thing I will start looking at some of the os's available for it, whatever that can be booted and taken off later. I am still pretty new to Commodores. I have a ton of ideas otherwise, too.

Thanks again!


August 2nd, 2003, 06:00 AM
er, I could have sworn I saw links there. I need to go to bed now, heh.