The Sony DSBK-1505 is the optional accessory board that provides analog input. This is the replacement for the DSBK-1504 and has all the same specifications. The board allows for composite and Y/C video (and two channels XLR audio) input to this VTR. This board is for the DSR-1500A NTSC VTR only. A firmware upgrade for all early DSR-1500As with serial numbers prior to 120001 is required. Contact your local Sony service center for information.