NB This Howto is around 5 years old, but its still linked to from some sources so I though I would keep it alive, the lirc bits are probably a little out of date by now

This howto is a quick description of how i got a pace rflink device (designed for TIVO) working on a standard RS232 serial port with lircd

Pace rf2link

The rf2link is a remote control extender for SKY and SKY+ systems that sends the control commands via the coax cable that is also used to send the picture to other televisions. These can be bought from http://www.pacelink.co.uk/rf2link.htm. These devices run of 9v power from the SKY/SKY+ box that can be switched on from the RF2 socket. Two varieties exist one of which allows the power to continue to the NEXT device along the coax and one that stops the power at the rf2link device, ONLY use the through power device IF you require the power at the next device, i.e. another remote extender. DO NOT ALLOW the 9v to reach your TV or your capture card! You have been warned!.

These are designed for a TIVO so two possibilities exist :-

1 – Cut off the jack plug
2 – Make a nice socket for the jack plug to plug in to

I chose number one. Next you will need some 1N4148 diodes or similar small signal diodes, a female DB9 socket and a plastic cover to mount the DB9 socket and hide away the 1N4148 diodes. These parts can be obtained from maplins http://www.maplin.co.uk or you local electronics shop.

Serial ports can signal from -9v to +9v (nominal) and can have voltages much lower than this. I assumed my serial port was 9v and used 4 diodes (0.6-0.7v drop per diode) and to stop the serial port putting any -ve voltages on the pacelink device.

DTR. -------->|---->|---->|----->|------- PACELINK Centre of cable

GND ---------------------------------------- PACELINK Ground of cable

The pace link device input drives into a 3.5k ish resistor so i suspect a few extra volts won’t hurt but their are a load of transistors next so i would not recommend any negative volts reaching them so a minimum of one diode always!.-

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I’m often hacking around with some device that has RS232 but at TTL levels and I quickly want to connect it to a PC for some testing or set-up, but I came across these wonderful devices ready to go out the box :-

TTL RS232 to USB convertors

Available from RS Components http://uk.rs-online.com/web/p/interface-development-kits/6877770/ there are 5V and 3.3V TTL versions available. They are not the cheapest things in the world but they are ready to go directly into your TTL RS232 level device and come on a standard 0.1″ pitch connector that also provides +5V if needed.