What IEC 60870-5-101S timestamp formats are supported?

The following two IEC 60870-5-101 slave protocol timestamp formats are supported:

CP56time 2a - Seven octets binary time, and 

CP24time 2a - three octets binary time

For details reference the IEC documents:
IEC 870-5-4 chapter 6.8
IEC 870-5-101 chapter 7.2.6.19

IEC 870-5-101 chapter 7.2.6.18