3Com 3C17700 - SuperStack 3 Switch 4900 Getting Started Manual page 15

Switch — Front View Detail 15
Figure 3 Switch 4924 — front view
Figure 4 Switch 4950 — front view
WARNING: RJ-45 Ports. These are shielded RJ-45 data sockets. They cannot
be used as standard traditional telephone sockets, or to connect the unit to a
traditional PBX or public telephone network. Only connect RJ-45 data
connectors, network telephony systems, or network telephones to these
sockets.
Either shielded or unshielded data cables with shielded or unshielded
jacks can be connected to these data sockets.