BBC is used to specify the Base Band Converter (BBC) to which each baseband channel is assigned. A value can be given for every channel. If any or all values are missing, SCHED will try to set to reasonable default values for VLBA and MKIV format observations.
Note that BBC assignments are arbitrary for VLBA systems since all BBCs can see all input IFs. However, for Mark III and Mark IV systems, there are strong constraints. For ``astronomical patching'', which is the only one currently understood, the odd BBCs must be connected to IF1 (IFCHAN 1N or 1A where 1N is normally LCP and 1A is normally RCP). Even BBCs must be connected to IF2 (IFCHAN 2N or 2A, where 2N is normally RCP and 2A is normally LCP).