<aside> <img src="/icons/map-pin_gray.svg" alt="/icons/map-pin_gray.svg" width="40px" /> Relevant Notes/Resources:
9 Serial Communication Interface
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It should tell you what voltage level represents what logic. In this case $+12\textrm{V}$ is logic 0 and $-12\textrm{V}$ is logic 1. We are interested in the data bits, which are bit 0 to bit 7. If you write down the logic for each data bit, you should get the following:
Now the easiest mistake most people make is writing the bits in the wrong order. Remember the LSB is transmitted first. So the following byte is transmitted:
$$ \%\underset{d_7}{0}\underset{d_6}{1}\underset{d_5}{0}\underset{d_4}{0}\underset{d_3}{0}\underset{d_1}{0}\underset{d_1}{1}\underset{d_0}{1}
$$
Make note of the placement of $d_n$ — notably the MSB and LSB. Converting the binary to hexadecimal gives:
$$ \%01000011 \to \$43 $$
Then, refer to the ASCII Character Code to determine the character in ASCII for $43.
The character being transmitted (in ASCII) is C.
As shown above, a character consists of a start bit, 8 data bits, and a stop bit. That means one character is $10\ \textrm{bits}$. Then, if we want to transmit $100\ \textrm{characters}$, that would be:
$$ 10\ \textrm{bits} \times 100 = 1000\ \textrm{bits} $$
Now let’s make note of the baud rate. For this question, it is:
$$ \textrm{Baud rate} = 200\ \textrm{bits/sec} $$
To determine the transmission time for $100$ character, that would be: