TTL and RS232

[Usman Rashid]

Hi,

I want to know that what is the different between RS232 and TTL.

I want to know that can we two RS232 to TTL converters back to back in the wire ??

[Sigurd]

Hi,

With the RS-232 standard a logic high ('1') is represented by a negative voltage (from -3V to -25V), while a logic low ('0') is a positive voltage (from 3V to 25V). With TTL (transistor-transistor logic), a logic low is 0V, and a logic high is usually the supply voltage (typical 3.0V on the nRF51). If you want use RS232 with the nRF5x, you need to add a RS232 transmitter/receiver, e.g. MAX232.

[Usman Rashid]

Thanks for the answer.

We have TTL to RS232 cable but when we add RS232 to TTL and then TTL to usb so we can not send the AT commands.

Is it possible to use the converter back to back in such configurations ?

[Sigurd]

What converter are you using ?