Bcc For Horizontal Parity Checking - Symbol PDT 1100 Product Reference Manual

BCC for Horizontal Parity Checking

The PDT 1100 supports horizontal parity checking for every transmission block to check
data transmission. A horizontal parity byte called BCC (Block Check Character) is
appended after the ETX of every transmission block. Every parity bit of BCC is set so that
all set bits at the same bit level (including a parity bit) in the transmission block characters
have an even number by binary addition, excluding SOH, STX, and functions SOH$ and
STX$. (For details about SOH$ and STX$ protocol functions which are unique to BASIC
3.0 interpreter, refer to the PDT 1100 Terminal Programmer's Guide, p/n 70-36099-xx.)
(Vertical Parity)
LSB
b0 b1 b2 b3
LSB
b0 b1 b2 b3
Figure A-3. Vertical Parity
[For 8-bit Data]
Character
Figure A-4. Horizontal Parity Checking
MSB
b4 b5 b6
Vertical Parity Bit
MSB
b4 b5 b6 b7
Horizontal Parity Byte
(BCC)
Specifications
Vertical Parity Bit
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A-7