ESC beeps when waiting for command

I have a 30A ESC. I use it to control a 1000KV (A2212) brushless motor.
I believe i succesfully initialized the motor to work betwenn 700 and 2000 ms.
I have two problems :

-It keeps beeping when I plug the ESC. It stops only after I send a command to writeMicroseconds between 700 and 2000 (to start the motor). After I send a lower than 700 command (to stop the motor), it starts beeping again.

-Even though I calibrated it to work between 700 and 2000, it only starts at 760. Why is that?

I would appreciate any possible help. Thank you!

Its a cheap bit of RC kit, not a precision engineered component, what are you expecting? If it flies
a model aeroplane, it meets its spec...

Sounds like it's working properly.

Calibration of your ranges on an air ESC normally sets the max throttle point and also the min signal for motor stop and arming. There will be a good deadband between zero throttle and the minimum startup throttle. This helps keep your fingers intact.

Thank you! Good to hear that.
One more thing. If I calibrate all my 4 ESC in that way (700-2000), will all of them have the same speed on let's say 1000 ms ?

Let me re-iterate: "Its a cheap bit of RC kit, not a precision engineered component" - so who knows? You'll
find out.

softt:
Thank you! Good to hear that.
One more thing. If I calibrate all my 4 ESC in that way (700-2000), will all of them have the same speed on let's say 1000 ms ?

What ESC is this? If it's the good ole yellow xxd 30a ESC clone of some type there's a good chance there's no external oscillator even. They just run flat out at the fastest their little internal clock can manage, they have a lot of variance. If it's for a multirotor it doesn't really matter. It doesn't care what it's current speed is , just if it needs less or more.

If you get an ESC with more precise clock and use a firmware thay allows for a governer mode you can drive them fairly accurately at a specific rpm.