Hi thanks for choosing Dell. You can use 1GB.
Hello,    I have S4128F-ON, and this switch should be connected to a Cisco switch with 1G copper cables,   can I use Transceiver, 1000Base-T, to do this connectivity?    S4100: saying this support  multifunction,1/10/25/40/50/100 GbE top-of-rack (ToR)  [URL]   thnx 
S4128F-ON- can support 1Gbps interfaces using