Serial Control - Mac

[BigbertII]

Does any one have a program which can send Serial commands from a Mac?
I want to make a program which you press a button on the Mac and it controls a device.

Cheers
Bert

[waynehoskins]

I don't know, but I imagine you may have a hard time. Software-wise it's not that hard, theoretically, but modern computers, particularly Macs, don't ship with 232 interfaces most of the time. USB-to-232 adapters aren't the same as having a real UART onboard, and sometimes that makes a difference, particularly when the hardware handshaking lines come into the picture.

Since MacOS is fundamentally BSD UNIX under the hood, presuming you have a 232 card, it should be as simple as echoing the character string you want to /dev/ttyS0, or maybe ttyS1, or some variation on that theme.

What sort of device do you want to control?

[BigbertII]

Its a simple projector so just
On/Off, change source, Blank freeze etc.

I'd have to use a USB > RS232 Interface sadly as it's a new mac we're using

Bert

[waynehoskins]

Fortunately, most projectors, or at least the ones I've used, don't use handshaking. You may have to adjust the baud rate and such, don't remember how you do that. I want to say it's in something like /etc/termcap on Ubuntu systems, but it's been a while. The Internet should know how to do that.

The one quick gotcha, one that I found after running pre-terminated cables in the air, is that projectors usually have their 232 port the wrong way, so I think it takes a null-modem cable with a female connector at the projector. That was a fun field-retermination.

Since it's a USB adapter, it may be /dev/ttyUSB-something, depending. You might tail -f the system log file (/var/log/messages, /var/log/syslog, or some such) when you plug the adapter in to see where it gets registered. Then it's a matter of writing the command strings out to the port. You might write the strings to their own files, and then it's just cat commandfile > /dev/ttyS0. Who knows, there might be software out there already, but generally Mac people aren't 232-based-integration people, so there might not be enough demand for there to be a program already out there.