scaner on network

What kind of scanner are you considering?

Assuming you have found a scanner that can be shared on a network, it should not need any "special" connection. Just like any other system, plug it into your existing switch (or hub, if that's all you have).

FWIW, you're better of with a switch, but that's a different question.

If you mean network monitor (sniffer, etc.) you should plug it ether to HUB or to specially preconfigured port on SWITCH. What is a difference? Switch works on following way: it receives frame on port, then analizes frame header and sends frame to specific destination port. Only exlusion is broadcast traffic. If you will plug sniffer to switch port it will capture only broadcasts or traffic destined to this host. But switches have ability to configure port as "monitoring" port where ALL trafficwill be copied.

If you mean network scanner to "ping" hosts/networks, then hardware does not matter because this software is working on Network level of OSI Model.

Good luck,

Mike