请教两个MTK的AT命令发送的问题

crossbet

1、我用一个串口工具往手机发AT指令，有时能响应，有时不响应。
2、发AT指令时，不带参数的可以返回值，带参数返回ERROR。
例如：
AT+CKPD指令：往手机发送按键，格式为AT+CKPD=?或者AT+CKPD=<keys>[,<time>[,<pause>]]
发送AT+CKPD=?返回OK
发送AT+CKPD=<1>返回ERROR
其他带值的指令也返回ERROR，不知道是否有什么开关没打开。

lander

3GPP AT spec:
实测发现 AT+CMEC=? 直接返回 ERROR,看下面的解释,则你要的CKPD可能由此也就不支持.

Mobile Termination control mode +CMEC
Table 65: +CMEC parameter command syntax
Command         Possible response(s)
+CMEC=[<keyp>[,<disp>[,<ind>]]]        +CME ERROR: <err>
+CMEC?        +CMEC: <keyp>,<disp>,<ind>
+CMEC=?        +CMEC: (list of supported <keyp>s),(list of supported <disp>s),(list of supported <ind>s)

Description
Set command selects the equipment, which operates MT keypad, writes to MT display and sets MT indicators. If operation mode is not allowed by the MT, +CME ERROR: <err> is returned. Refer subclause 9.2 for <err> values.
Test command returns the modes supported as compound values.
Defined values
<keyp>:
0        MT can be operated only through its keypad (execute command of +CKPD cannot be used)
1        MT can be operated only from TE (with command +CKPD)
2        MT can be operated from both MT keypad and TE