多谢各位
我找到这个模块的说明书了,上面的意思应该是ttl电平,至于为什么加上rs232还是不太清楚
serial data: rxa, rxb, txa, and txb
the tmp supports two full duplex serial channels. all four connections are at ttl
levels, all support variable baud rates, and all can be controlled from the appropriate
screens in sirfdemo toolkit a ttl to rs232 conversion is necessary to directly
communicate with a pc serial port.