tp rj45/15现成的电缆6XV1850-2LH20，2米长。

RJ45口的定义：
Pin No. Signal Name Function
1 TD TP– / Transmit +
2 TD_N TP– / Transmit –
3 RD TP– / Receive +
4 – –
5 – –
6 RD_N TP– / Receive +
7 – –
8 – –

15pin sub-d 定义：
Pin No. Signal Name Function
1 MEXT External ground, shield
2 CLSN Collision +
3 TRMT / TPETXD Transmit + / TPE Transmit Data +
4 Ground Ground 5 V
5 RCV / TPERXD Receive + / TPE Receive Data +
6 M 15 V Ground 15 V
7 TPE_SEL Switchover AUI/ITP
8 Ground Ground 5 V
9 CLSN_N Collision –
10 TRMT_N / TPEXTXD_N Transmit – / TPE Transmit Data –
11 Ground Ground 5 V
12 RCV_N / TPERXD_N Receive – / TPE Receive Data –
13 P15 V +15 V
14 Ground Ground 5 V
15 – –