i have a summit200-48,
1- i do factory reset using> unconfigre sw all
2- then i set ip address on Default vlan (172.16.100.1) now each computer that connected to any of 48 switch ports can ping valn ip(172.16.100.1).
3- now i make loop between 2 ports of switch for some seconds.
4- now ping is timed out.
5- now i remove loop then only computers connected to ports 1-24 can ping default vlan and 25-48 have timeout. in another way now i have 24port switch!
6- with reset everything is ok.