For those wanting to use SiliconDust HDHomeRun Prime (HDR3-CC) with MythTV, it does work with Comcast. Tell Comcast you need a CableCard for a Tivo-like device; they've never heard of HDHomeRun or MythTV. See http://www.mythtv.org/wiki/Configuring_MythTV_for_the_HDHomeRun_Prime for MythTV setup instructions. Also, SilicodDust runs a super helpful forum http://www.silicondust.com/forum/viewforum.php?f=42. Note that MythTV 0.24 with up to the day fixes (or 0.25) is REQUIRED. Also, be sure to update the HDHomeRun firmware to the latest beta via hdhomerun_config_gui. You can test the HDHomeRum functionality without having the very latest MythTV support by using hdhomerun_confg_gui (you just can't get MythTV to use it until you update).
I had 2 comcast techs come on site on consecutive days to install the CableCard; neither had heard of HDHomeRun Prime or knew where to find the CableCard/Unit/Data ids needed to activate/pair. These can be found from the webpage built in to the HDHomeRun, just put the ip address of the HDHomeRun Prime (eg, 192.168.1.5) into a browser on any computer on your home network. The id information required for activation/pairing can be found via CableCard Menu -> CableCard Pairing. There is even a phone number there you have to call to do the activation/pairing.
The initial install was only partially successful (the channel listings were downloaded but nothing would play via hdhomerun_config_gui, VLC indicated DRM protection), requiring a second tech visit. It turns out the setup was wrong on Comcast's end which when corrected allowed all subscribed channels to work. See http://www.9thtee.com/sdforum.htm for detailed symptoms of the problem and SiliconDust's description of what Comcast needed to do to resolve it.
Good to hear you have yours working. The comcast cable activation number is noticably better at activations than they were a month ago. They are still having issues with provisioning a device to receive the correct channels for the subscribers package, much of which is an issue with the local account levels.
One note: the ip address for the homerun is allocated by DHCP from your router so it may not be the same as yours on everyones network.
Although this is a very old thread, I'd just update my experience on CableCard Activation with HDHomerun Prime in 2013.
I tried to activate the card via comcast.com/activate; it told me to wait for an hour but in vain. I tried the next day twice, still in vain although the wait time was reduced to 45 minutes. I then called several service numbers, including the one showed up in HDHomerun's cable card message, but none of them worked. Along the way I also tried online chat and it was useless too. Finally a customer service gave me the number 'specifically' for cable card activation: 877-405-2298.
A very nice lady picked up, and she asked me what I needed a cable card for, Tivo, HDHomerun or something else. You know you are at the right department when she said HDHomerun.
She helped me with the registration and then activated my card from her end. Finally.
Same great experience with that 877 number, with my HD HomeRun Prime, M-card, and Win7 WMC. They even had notes on navigating MCE and HDHRP menus, to get the data/host/cablecard info. Once they sent the signal, the HDHRP showed service, and MCE has worked great since.
I have been trying to get my HDHomeRun Prime cablecard activated. I have a Mac and I cant figure out where to get the device or hostid...
When I called the cablecard service number and talked with someone there they didnt know where to find it either...
Can someone help me please? Where do I find the information needed? He said he was looking for the hostid? Where can I find that? I installed the HD HomeRun Config util for mac but couldnt see any information for a host id?
Launch HDHomeRun Config select the device you have (incase there is more than one), then the Webpage tab. --> Cable CARD Menu --> Cable CARD Pairing: That should give you the information you need to give to Comcast..
I'm guessing it's more because you're an Apple user who needed to take an extra moment to remember technical things really quite often do not hold your hand through every step of the way. Most network appliances[devices] will have a page accessible via port 80 on it's IP address. It's not rocket science, but it's also not a dumbed down Apple product either.