TWC New York has sent an internal memo to customer service reps requiring them to get the model number of the Series 3 unit before they will make an installation appointment for the cable cards. The internal memo lists two serial numbers that they will accept: TDC64825 0A TDC64825 0B However, the correct model number is "TCD" and not "TDC." If you tell them that you have the correct model number, TCD648250B they will not set up the appointment. The Customer Service guy (clueless) said that he would have to check with IT and will get back to me in one or two days before he could set up the appointment. Seems that they can't admit that they might have transposed some digits.