QFX5200, EX3400, EX3300, EX2300, and EX2200 switches cannot be part of any mixed Virtual Chassis.
taken from documentation
additionally:
EX4200 | 2 ports on rear panel | None | Any uplink module ports (SFP, SFP+, or XFP) or through an SFP+ port on the EX4200-24F switch Note: You cannot set a 1000BASE-T copper SFP transceiver (EX-SFP-1GE-T) connection as a VCP on EX4200 switches. |
regards
alexander