# Does transmitting break over FTDI chipset yield a binary 0 received on the receiving end?

I send breaks (using Tx) over FTDI FT232R chipset using two ways:

a. Using the BREAK command in the operating system (Windows 7 and Ubuntu)
b. Gating the Tx line for an arbitrary period


I connected the Tx pin to the Rx pin of the FT232R (loopback test) and used a variety of serial consoles to read the Rx input

I always got a binary 0 in both case. Each case individually behaved so:

• i. Using the BREAK command, I recieved binary 0 when the BREAK command was made active (BREAK is active low)
• ii. When gating the Tx line, I recieved binary 0 when I forced the Tx line low

This does not seem right to me.

The only time when the UART Rx can get "confused" between BREAK and a binary 0 transmission, is when the BREAK switches the line low for exactly 9 bits duration and then brings the line back to high (making the Rx side misinterpret as a stop bit), but this breaks a definition of BREAK which requires the line to be held low for at-least 10 bits duration.

So my questions are:

1. Is this expected behaviour ?
2. If you do a loopback test on your FTDI chipsets can you reproduce this behavior (implying I have bad drivers/faulty chipset)