LIRC guide for FreeBSD

Andrew Milton akm at
Fri Mar 16 14:48:19 UTC 2007

+-------[ Torfinn Ingolfsen ]----------------------
| On Wed, 14 Mar 2007 19:50:42 -0400
| Joe Auty <joe at> wrote:
| > The piece I'm missing is getting LIRC listening on a device node so
| > that it can communicate with my IR Blaster connected to my serial
| > port.
| I *think* that the problem is related to the fact that IR Blasters are
| using the serial port in a non-standard way.
| Instead of using the Tx signal to transmit data, they are using the DTR
| signal. This page seems to support that view:
| Thus, you need a special driver for the serial port which allows it to
| work in this way. It is probably a year or two since I looked at it,
| but the problem then was that LIRC's "driver" for serial ports was
| totally Linux-specific, not very clean code, and not easy to port over
| to FreeBSD. So nobody did make a LIRC serial port driver for FreeBSD .

You don't really "send" or "receive" data to and from IR devices.

You don't really need a driver, you just need to be able to strobe the control
line at the right frequency, in the right burst lengths. You can do it from userland 
if you need to.

The serial drivers for LIRC simply monitor the relevant pin and decode the
incoming data. You can do this in userland, without needing a lirc kernel
module to watch the serial port.

The reason they use the control lines instead of tx/rx is that you don't need
to be concerned with baud settings on the port.

Andrew Milton
akm at

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