SOLVED - Serial1.begin(57600) = 57.600 kHz ?

//Leo_passthru
// Allows Leonardo to pass serial data between 
// fingerprint reader and Windows.
//
// Red connects to +5V
// Black connects to Ground
// Green goes to Digital 0
// White goes to Digital 1

void setup() {
  Serial1.begin(57600);
  Serial.begin(57600);
}

void loop() 
{  
  while (Serial.available())
    Serial1.write(Serial.read());
  while (Serial1.available())
    Serial.write(Serial1.read());
}[code]

[/code]

No. Baud rate = bit data rate in bits/second for serial data transmission.

"Frequency" does not apply because the data are transmitted asynchronously, with arbitrary pauses.

The first line I know.
Baud rate it is not related with frequency ?
In serial communication we have 5V pulses with some frequency ?

In serial communication we have 5V pulses with some frequency ?

No. You don't send "pulses", you send line levels.

Consider the differences between serial transmission of a data byte == 0b10101010, a data byte == 0b11110000 and a data byte == 0.

so serial communication is not only - 0 and 1 ?

You REALLY need to read up on serial communications!

Beware, there are many. The Arduino uses the TTL voltage level variation of the ancient RS232 serial protocol.

I will check by oscilloscope - easier

As my old chemistry professor used to say, two weeks of working in the laboratory can save you 1/2 hour of reading in the library.

I expect to connect oscilloscope in less than in 2 weeks.

That is certainly encouraging!

Thanks for some explanations.
Regards
Ted

this camera has 8 kHz modulated pulses with strange amplitude 0.3V

I don’t see any problem saying that a 57600bps line has a data rate of 57.6kHz.
That doesn’t give you the real data bandwidth, or the shape of the waveform, and neglects the extra bits added to the data for framing, that aren’t RealData.
But it’s close enough until a bettter question comes along.

ted:
The first line I know.
Baud rate it is not related with frequency ?
In serial communication we have 5V pulses with some frequency ?

The distinction is that there are common signaling schemes that send more than 1 bit of information per signalling period. Thus it is not true in general that baud rate is equivalent to signaling rate. In the case of Arduino serial the signalling is binary, that is 1 bit of information per signalling period, so the baud rate and the signalling rate are the same for this case.

ted:
The first line I know.
Baud rate it is not related with frequency ?
In serial communication we have 5V pulses with some frequency ?

Well a 57.6kHz square wave would be 115200 baud as there are 115200 transitions per second,
but we don't talk of frequency for digital baseband, that's reserved for analog signals or modulated
carriers.

Baud rate is defined as the symbol transitions per second, not bits per second.

Some strange things on USB camera.
Expected 5V pulses they but are 0.3V.
The signals on Rx and Tx are very similar.
So USB not always is using 5V pulses

Mentioned above definitions are know to me, but relation to frequency is not clear.

expected pulses

After reading through the thread a few times, I gather that you're trying to use a USB camera of some sort on an Arduino Leonardo, but I'm not really certain of your intent. That's why it's always helpful to give a brief synopsis of your project when starting a new thread. If this is correct, then it's almost certainly not going to happen.

ted:
Mentioned above definitions are know to me, but relation to frequency is not clear.

I am not using arduino ,just regular USB camera, in drawing above arduino is the part of copied picture (ignore it ) look only on right side - pulses.
This is for better understanding USB serial communication.

I see where I've gone wrong. I guess the Leonardo comments in the code from the original post, the Arduino function call in the title, the picture of an Arduino in above picture, and reading a post on forum.arduino.cc distracted me from the critical initial reference to USB on thread post #15.