明基西门子EL71数据连接意识图

刷机线必须有一块类似PL-2303芯片的USB to Serial芯片
自己做刷机线其实很麻烦，你可以去淘宝上找一条DCA-100刷机线，20块就可以了，然后用客服升级包重新写入固件，应该可以解决你说的问题。

实在想自己做的话，查到了NANO口的引脚定义，你看看吧

明基西门子NANO口接线定义：

QUOTE:
[Raspinovka] the joint “Of nano” for BenQ-Siemens:
(It is used in the models: A31, S68, AF51, C/M81, EF71, SL91, E/EL71, E/EF81)

1- RTS (readiness for the reception of data);
is 2nd CTS (readiness for the reception of data);
3- OF TXD (data from the telephone to [kompu]);
4- RXD (data from [kompa] to the telephone);
is 5th GND (general);
6- DCD (good signal “of carrier” on the line);
7- POWER (charging, the nourishment of the microcircuits of cable from the telephone);
is eighth GND_MIC (general for the microphone sets, in the model Of [e]71 it performs the role of antenna for the built-in Fm- radio receiver);
9 MICEA_AC (signal from the microphone sets);
10 STEREO2 (right sonic stereo-channel for stereo-sets or mono for mono-s