4.7 Case Study of the Development …
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considering sequence plots at a slower rate, data transmission is still correct. With
this method, two overlapping transmissions permit the simultaneous transmission of
two messages at different data transmission speeds. In order to support transmission
with two data transmission speeds, both transmissions must have their own filled
frames, including a start bit, a stop bit(s), and data bits, then this data is correct when
reading the same information on two different speeds.
Another standard data transmission speed is 115,200 baud, which is 12 times
faster than 9600 baud. This means that 12 bits are transmitted for each one data
bit transmitted at 9600 baud. To protect against errors in the frame structure, the
complete package should fit into these 12 bits. This package typically consists of a
wait label bit, a start pause bit, eight data bits, and two stop bits for a total of 12
bits. This 12-bit package must externally look quite similar to the permanent “1” bit
transmitted at the same time at a speed of 9600 baud for the encVerifier program
to still identify data transmission at 9600 baud. There is also some “inflexibility” in
which bits a waveform can be specifically created, to make it look like slower data
transmission, since a header label bit and a start bit along with two stop bits should
always remain fixed. This means that if the transmission at 9600 baud transmits a
label bit, then the transmission at 115,200 baud can match this in 11 of the 12 bits;
but if it is a pause, then the best that can be arranged is 9 out of 12 bits. It turns out
that both of these methods are acceptable to look like a data transmission speed of
9600 baud. These two scenarios are considered in Figs. 4.39 and 4.40, respectively.
In these figures, the top data transmission package is sent at 9600 baud, and the lower
transmission package is sent at 115,200 baud.
Since the lower data transmission is 12 times faster than the upper one, the lower
data communication frame represents 1 bit in the upper data communication frame
and its shape is formed to look as similar as possible to the bit from the upper frame
it represents.
Label bit transmissions at lower speeds can be used to embed 1 bit of additional
information, including the key. Signal forming for faster data transmission to simulate
a slower transmission, more accurately represents the label bit, setting it so that 11
of the 12 bits are the same. One information bit embedded in the data section of a
Fig. 4.39 The correct RS232 frame at a data transmission speed of 115,200 baud may look like
label bits
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considering sequence plots at a slower rate, data transmission is still correct. With
this method, two overlapping transmissions permit the simultaneous transmission of
two messages at different data transmission speeds. In order to support transmission
with two data transmission speeds, both transmissions must have their own filled
frames, including a start bit, a stop bit(s), and data bits, then this data is correct when
reading the same information on two different speeds.
Another standard data transmission speed is 115,200 baud, which is 12 times
faster than 9600 baud. This means that 12 bits are transmitted for each one data
bit transmitted at 9600 baud. To protect against errors in the frame structure, the
complete package should fit into these 12 bits. This package typically consists of a
wait label bit, a start pause bit, eight data bits, and two stop bits for a total of 12
bits. This 12-bit package must externally look quite similar to the permanent “1” bit
transmitted at the same time at a speed of 9600 baud for the encVerifier program
to still identify data transmission at 9600 baud. There is also some “inflexibility” in
which bits a waveform can be specifically created, to make it look like slower data
transmission, since a header label bit and a start bit along with two stop bits should
always remain fixed. This means that if the transmission at 9600 baud transmits a
label bit, then the transmission at 115,200 baud can match this in 11 of the 12 bits;
but if it is a pause, then the best that can be arranged is 9 out of 12 bits. It turns out
that both of these methods are acceptable to look like a data transmission speed of
9600 baud. These two scenarios are considered in Figs. 4.39 and 4.40, respectively.
In these figures, the top data transmission package is sent at 9600 baud, and the lower
transmission package is sent at 115,200 baud.
Since the lower data transmission is 12 times faster than the upper one, the lower
data communication frame represents 1 bit in the upper data communication frame
and its shape is formed to look as similar as possible to the bit from the upper frame
it represents.
Label bit transmissions at lower speeds can be used to embed 1 bit of additional
information, including the key. Signal forming for faster data transmission to simulate
a slower transmission, more accurately represents the label bit, setting it so that 11
of the 12 bits are the same. One information bit embedded in the data section of a
Fig. 4.39 The correct RS232 frame at a data transmission speed of 115,200 baud may look like
label bits