Jargon, Terminology, Terms ....

[Shannen Durphey]

timsiford at hushmail.com wrote:
> 
> Is there a difference between Mask, Broadcast Code, and Scan ID?  I know
> that Scan ID is at position 8008 for the 730 TPI F and Y bodies.  This is
> '8D'.  However, isn't that also the Mask?  Is broadcast code any different?
>  Does BCC stand for Broadcast Code C..... .. .?
> 
> Too many words .. head is going to explode ....
> 
> Tim
Wow.  Isn't this stuff in the FAQ?  If not, it should be.

Here's some from last night's unsent reply:

> BCC= four letter/four number code on a sticker placed by GM over the
> window in the eprom.
> 
> BCC is application specific.  More than one BCC can be released for
> the same application.  Sometimes new BCC's 
> replace or "supercede" old BCC's.  Sometimes they released to fix
> special situations (electrical noise in the cell phones is a good
> example).  Sometimes they are for small variations between cars.
> (California emissions vs Federal).
> 
> Mask id is contained within the prom.  This is cut-n-pasted from one
> of Ludis' letters:
> 
> > The mask id is determined by checksumming the chip's program code and
> > table headers.  (The mask id byte in the chip is ignored in case it was
> > set to experimental mode.)


and the stuff below is from just a couple of weeks ago.  Now I can
tell who's paying attention!
BTW, FYI, BCC= BroadCast Code.

Shannen

> > 
> Scan id and BCC are for technicians in the shops, records at GM.  The
> scan id is displayed by a scantool.  It is a number in the prom
> designed to be used as a reference in finding the latest calibrations
> or pinpointing calibrations that have been replaced due to
> "concerns."  The scan ID is 4 digits long, and different calibrations
> can use the same one.  Using it effectively requires an idea of the
> year of the car, along with engine size, ecm number, and/or a couple
> of other small details.
> 
> BCC, Broadcast code, is a four letter/four number code used to
> identify a specific calibration.  By using a book or list, the bcc
> will reveal the year, engine size, ecm#, trans type, and other info. 
> I know of no instance where 2 different calibrations have exactly the
> same BCC.
> 
> Mask id is a number within the data in the prom.  It less specifically
> identifies the general calibration family.  There are sometimes
> variations on a single mask id, some of which are major, some of which
> are not as major.  
> 
> Knowing only the BCC can reveal the scan id and ecm number.  Knowing
> only the scan id can reveal a few different ecm's and BCC's.  Knowing
> only the mask id can reveal several different ecm's and multiple bcc's
> for each ecm. 
> Shannen
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