From MiniPro Community Wiki
Difference between TL866A and TL866CS
The TL866A has the ICSP header and TL866CS does not, otherwise the devices are the same.
This means that TL866A supports (in addition to all the chips TL866CS supports):
- Microchip ICSP support for some chips (in circuit programming)
- ICSP support for ATmega and SYNCMOS MCU SM89xxx SM59xxx (in circuit programming)
- AT45DBxxxx ICSP, programmable only on TL866A