[mythtv-users] HP MCE blasters with 2 ports: 2 blasters or 1?

[Jan Ceuleers]

On 03/15/2013 02:38 PM, Brian J. Murrell wrote:
> Yeah.  I guess I will keep that Acer one in duty to control 2 STBs
> (DTAs in fact) instead of having to use 2 of these HP units.

Careful: when you have two of the same devices you have to be able to
tell them apart. Otherwise the device names might change from one boot
to the next, and you won't know which-one to use to control a given STB.

You'll probably need to create udev rules to make the device names
persistent, triggering them based on some property by which you can tell
your USB IR emitter devices apart, such as a serial number. Here's an
example for the IR emitters that are embedded in my Hauppauge HVR1900
tuners, alongside the M$-branded but Philips-powered USB MCE
receiver/transmitter:

# Create a persistent name /dev/lircp0 to tuner SN 7300-00-F06D3877
SUBSYSTEM=="lirc", KERNEL=="lirc[0-9]*",
ATTRS{manufacturer}=="Hauppauge", ATTRS{product}=="WinTV",
ATTRS{serial}=="7300-00-F06D3877", SYMLINK+="lircp0"

# Create a persistent name /dev/lircp1 to tuner SN 7300-00-F06C9907
SUBSYSTEM=="lirc", KERNEL=="lirc[0-9]*",
ATTRS{manufacturer}=="Hauppauge", ATTRS{product}=="WinTV",
ATTRS{serial}=="7300-00-F06C9907", SYMLINK+="lircp1"

# Create a persistent name /dev/lircp2 to tuner SN 7300-00-F06EFBC0
SUBSYSTEM=="lirc", KERNEL=="lirc[0-9]*",
ATTRS{manufacturer}=="Hauppauge", ATTRS{product}=="WinTV",
ATTRS{serial}=="7300-00-F06EFBC0", SYMLINK+="lircp2"

# Create a persistent name /dev/lircp3 to tuner SN 7300-00-F07801CC
SUBSYSTEM=="lirc", KERNEL=="lirc[0-9]*",
ATTRS{manufacturer}=="Hauppauge", ATTRS{product}=="WinTV",
ATTRS{serial}=="7300-00-F07801CC", SYMLINK+="lircp3"

# Create a persistent name /dev/lircp4 for the USB MCE remote
SUBSYSTEM=="lirc", KERNEL=="lirc[0-9]", ATTRS{manufacturer}=="Philips",
ATTRS{product}=="eHome Infrared Transceiver", ATTRS{serial}=="PH00Sn5D",
SYMLINK+="lircp4"

> I did try taking the emitter cable from my Acer unit and plugging
> it into the HP unit to see what I could discover but I was unable
> to get anything out of the emitter (I even viewed the emitter with
> a digital camera and didn't see anything).

I may have been lucky, but I have indeed been able to interchange
blasters between emitter devices.

> I know the HP device is working at least marginally as irw sees
> commands from a remote.

Try fiddling with irsend SET_TRANSMITTERS.

Cheers, Jan