Well, lets
see....  if your on a PC, I think if you type at the DOS prompt
c:\> debug c800 
    That's assuming that the controller card is set to the
standard address
 of C800. C800 is the default for PCs but the cards can be addresses to
 different addresses. Checkit is handy for finding the card address.  Also
 the code doesn't usually start right at the biginning of the ROM. It starts
 at an offset of 5 in most controllers so you'd use debug then "g c800:5".
 I've seen a couple of controllers that started at 2 and I think I remember
 one that started at 10. 
 
NO!
<pedantic>
C800 is NOT the address!  It is the SEGMENT component of a two part
address.  But when used as STATED: g C800 , it would NOT cause a branch to
C800:0 as intended!  Instead, it would go to OFFSET C800 of the current
segment!  xxxx:C800
If you want offset 0 of segment C800, then the command must be: g C800:0
NOT g C800 !!!!!!!!!!
g C800:5 would, indeed, be correct for an offset of 5 within segment C800
BUT "g C800" is NOT going to work.
</pedantic>