HP ProCurve 3400cl-48G Installation And Getting Started Manual page 80

Switch Ports and Network Cables
Twisted-Pair Cable/Connector Pin-Outs
B-6
For 100 Mbps connections to the ports, use 100-ohm Category 5 UTP or
STP cable only, as supported by the IEEE 802.3u Type 100Base-TX stan-
dard.
For 1000 Mbps connections, 100-ohm Category 5e or better cabling is
recommended.