HEIDENHAIN MANUALplus 620 Technical Manual page 1776

Word length
Data bits
Transmission
reliability:
Parity bit
1776
Define whether a character is transmitted with 7 or 8 data bits.
MP_dataBits
Data bits in each transferred character
Available from NCK software version: 597 110-01.
Format: Selection menu
Selection: 7 bits
7 bits are transferred for each character transferred
8 bits
8 data bits are transferred for each character transferred
Default: 8 bits
Access: LEVEL2
Reaction: NOTHING
The parity bit helps the receiver to detect transmission errors.
The parity bit can take three different forms:
No parity (NONE): There is no error detection
Even parity (EVEN): The transmitter counts bits with a value of one. If the
number is odd, the parity bit is set to one, otherwise it is cleared to zero. The
sum of set data bits and the parity bit is therefore always even. Upon
receiving a word, the receiver counts all of the set bits, including the parity
bit. If the count is odd, there is a transmission error.
Odd parity (ODD): The parity bit is chosen by the transmitter so that the total
number of all the set bits is odd. An error will thus be detected if the receiver
observes an even number of set bits in its evaluation.
Example: The letter "z" corresponds to the bit sequence: 1 1 1 1 0 1 0
Parity bit:
With even parity = 1
With odd parity = 0
MP_parity
Specifies the type of parity checking
Available from NCK software version: 597 110-01.
Format: Selection menu
Selection: NONE
No parity formation
EVEN
Even parity
ODD
Odd parity
Default: NONE
Access: LEVEL2
Reaction: NOTHING
HEIDENHAIN Technical Manual MANUALplus 620