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Comcast is transitioning away from analog to digital. For those customers not upgrading to digital TV's, they are providing free digital to analog converters (DTA's). Traditionally, their full featured set top boxes (STB's) received all sorts of information such as encryption keys, guide data, etc via an out of band (OOB) POD interface. This is a special receiver that tunes frequencies outside of the normal TV frequencies. One of the pieces of information that's transmitted is a table that maps station callsigns and virtual channels (the integer channels that the STB's present to the user and are used by TV Guide, Schedules Direct, zap2it, etc) to RFchannel.program number that clearQAM TV's use. For example, Schedules Direct and Comcast may say FOODTV is channel 35 but a clearQAM capable TV plugged directly into the line will report it as 78.4. This would also traditionally require one to use the MythTV channel editor and manually input the frequency and program number for each channel and associate the xmltvid. Since Comcast is handing out DTA's for free, they are severely cost reduced and don't have a POD interface. In its stead, they are transmitting the virtual channel table in-band (i.e. tuneable with a conventional clearQAM tuner) to allow the DTA's to do the virtual channel mapping.

The scte65scan tool

scte65scan is a utility that will read the in-band virtual channel tables and automate the mapping of frequencies and program numbers to virtual channels and xmltvids.

( this link contains important information about compiling libhdhomerun and scte65scan for support of the Silicondust_HDHomeRun on Mythbuntu 9.10 )

A quick overview of the process is as follows:

  • Find the VCT_ID for your lineup. This can be done by obtaining a DTA or STB and reading it from the diagnostic page. Alternatively, it can also sometimes be found by inspection through an examination of the text-mode output of scte65scan
  • Generate SQL for importing into MythTV (e.g. `scte65scan -f3 -V your_VCT_ID itfile > vct.sql`
  • If you seem to be missing channels (e.g. your local broadcast HD), try the -p option to scan the full channel table (e.g. via HDHomeRun `scan -H FFFFFFFF -p -f3,9 -V 3092 us-Cable-Standard-center-frequencies-QAM256 > vct.sql`)
  • Import the SQL into MythTV (e.g. `mysql mythconverg < vct.sql`)

The next time it is run, mythfilldatabase will detect the virtual channel number in the 'freqid' and/or 'channum' field of the imported SQL and fill in the xmltvid for you if you are using Schedules Direct. Be sure to enable the channels at Schedules Direct prior to running mythfilldatabase. Alternatively, you can use the following SQL, which will also help by setting the callsigns to the same so that they don't double up in the UI:

UPDATE channel AS c1,
       channel AS c2
SET    c1.callsign = c2.callsign,
       c1.xmltvid  = c2.xmltvid,     =,
       c1.icon     = c2.icon
WHERE  c1.sourceid=<<scte source id>>
   AND c2.sourceid=<<SD source id>>
   AND c1.channum = c2.channum;

There are several things that are tricky about this.

  • The SQL that scte65scan generates assumes that it can start the mplexids for the transports can start at 1, which only works if this is the only DVB source in the database. The latest SVN deals with this by multiplying the sourceid by 1000 and adding it to the RF channel number to generate mplexid's much like mythtv generates channel ID's by multiplying the sourceid by 1000 and adding it to the cable channel number. Otherwise you'll get conflicts, so you'll have to manually adjust the mplexid values to an unused range.

For more information, visit the scte65scan project page

How to determine VCT_ID using a Full Set Top Box

For those without DTAs, it is still possible to determine the VCT_ID using most set top boxes. This method is tested on Motorola DCH-3200s and DCH-6200s, but should work for other Motorola models as well.

  1. Power on your box.
  2. Press "Power" on the remote to turn off the box. IMMEDIATELY press "OK" on the remote. You should see a long list of menus numbered d01-d18.
  3. Select option d6, "Current Channel Status."
  4. You should see VCT ID listed on this page. It may only be one or two digits, which should correspond to the last one or two digits in the VCT_ID. You can run the scte65scan tool with no options to see the available tables. If the VCT_ID on your set top box is "10" and the scte65scan program shows that one of the VCTs is 3010, then this is your VCT_ID. Take note of both the decimal and hex VCT_ID and enter them in the table below.

How to determine VCT_ID using the Pace DC50X

  1. Make sure the unit is on.
  2. Hold down the INFO button until you see the diagnostics screen.
  3. Press +/- until you see the VCT_ID. This should be the 2nd screen

Here are screenshots and unboxing:

Here is the mythtv-user post about scte65scan:;#382657

Update 10/31/09: Pace DC50X box you get from comcast may no longer have the screens listed in the screen shots above. Step 3 above will be different. Use the channel up or down button to go to the Virtual Channel Map and press enter on the remote, it will give you the channel list, complete with frequencies. (along the top of the screen will give the VCT ID)

VCT_ID by Location

Please post your Zip code, city, and VCT_ID in the table below to allow others without DTAs to determine a probable/possible VCT_ID choice.

Important! All locales will see multiple VCT_IDs, only one of them applies to your locale. That is the point of this table. See the instructions above and only post one VCT_ID: the one for your exact location. Please do not post all the VCT_IDs you see! Rarely, the same ZIP code can overlap locales and have different VCT_IDs. This is why it is essential that you provide all information to distinguish one from the next.

Note: Please put each ZIP code in a new entry. Adding extra ZIP codes to an existing entry breaks sorting of the table. Please do not leave any fields blank. Figuring out the decimal and hex values are explained above.

State City Zip Code VCT_ID (decimal) VCT_ID (hex)
California Fremont 94536 3078 0x0c06
California Livermore 94551 3038 0x0bde
California Danville 94526 3053 0x0bed
California Foster City 94404 3082 0x0c0a
California Martinez 94553 3055 0x0bef
California Fairfield 94534 3087 0x0c0f
California Fairfield 94533 3087 0x0c0f
California Suisun 94585 3087 0x0c0f
California Los Gatos 95032 3010 0x0bc2
California Milpitas 95035 3020 0x0bcc
California San Carlos 94070 3086 0x0c0e
California Woodside 94062 3062 0x0bf6
California Mountain View 94040 3059 0x0bf3
California Mountain View 94041 3059 0x0bf3
California Mountain View 94043 3059 0x0bf3
California Pleasanton 94566 3038 0x0bde
California San Francisco 94110 3013 0x0bc5
California San Jose 95119 3065 0x0bf9
California San Jose 95124 3001 0x0bb9
California San Jose 95132 3065 0x0bf9
California San Jose 95136 3001 0x0bb9
California San Jose 95136 3065 0x0bf9
California Santa Clara 95051 3058 0x0bf2
California Santa Clara 95054 3058 0x0bf2
California Santa Rosa 95405 3003 0x0bbb
California Seaside 93955 3092 0x0c14
California Sunnyvale 94087 3018 0x0bca
California Sunnyvale 94085 3018 0x0bca
California Union City 94587 3090 0x0c12
Georgia Dunwoody 30338 3022 0x0bce
Georgia Marietta 30066 3021 0x0bcd
Georgia Tucker 30084 3001 0x0bb9
Illinois Lisle 60532 3052 0x0bec
Illinois Darien 60561 3040 0x0be0
Maryland Baltimore 21209 3011 0x0bc3
Maryland Hanover 21076 3003 0x0bbb
Maryland Silver Spring 20904 3012 0x0bc4
Maryland Waldorf 20602 3028 0x0bd4
Massachusetts Ashland 01721 3022 0x0bce
Massachusetts Bedford 01730 3002 0x0bba
Massachusetts Bolton 01740 3005 0x0bbd
Massachusetts Wayland 01778 3003 0x0bbb
Massachusetts Cambridge 02139 3029 0x0bd5
Massachusetts Cambridge 02140 3029 0x0bd5
Massachusetts Florence 01062 3025 0x0bd1
Massachusetts Haverhill 01835 3004 0x0bbc
Massachusetts Marlborough 01752 3022 0x0bce
Massachusetts North Attleboro 02760 3017 0x0bc9
Massachusetts Northampton 01060 3025 0x0bd1
Michigan Ann Arbor 48104 3023 0x0bcf
Michigan Grand Rapids 49508 3003 0x0bbb
Michigan Lansing 48917 3018 0x0bca
Michigan Plymouth 48170 3001 0x0bb9
Michigan Algonac 48001 3005 0x0bbd
New Jersey Skillman 08558 3001 0x0bb9
Oregon Portland 97212 3011 0x0bc3
Oregon Tualatin Valley 97006 3003 0x0bbb
Oregon Gresham 97080 3034 0x0bda
Oregon Lebanon 97355 3009 0x0bc1
Oregon Corvallis 97333 3029 0x0bd5
Tennessee Chattanooga 37416 3028 0x0bd4
Washington Auburn 98002 3100 0x0c1c
Washington Bothell 98021 3042 0x0be2
Washington Bothell 98011 3113 0x0c29
Washington Everett 98208 3127 0x0c37
Washington Kirkland 98033 3116 0x0c2c
Washington Redmond 98053 3117 0x0c2d
Washington Seattle 98118 3092 0x0c14
Washington Olympia 98502 3020 0x0bcc
Washington Spokane Valley 99037 3021 0x0bcd
California Oakland 94618 3072 0x0c00
Iowa Iowa City 52245 3110 0x0c26