HP ProBook 6540b - Network); Modem)

Connector pin assignments
Maintenance and Service Guide 9–3
RJ-45 (network)
RJ-11 (modem)
Pin Signal
1 Transmit +
2 Transmit -
3 Receive +
4 Unused
5 Unused
6 Receive -
7 Unused
8 Unused
Pin Signal
1 Unused
2Tip
3 Ring
4 Unused
5 Unused
6 Unused