User`s manual

EM1500 User’s Manual www.rabbit.com 43
Character size
This is the number of bits per character, not counting start, parity or stop bits. The
only valid entries for this field are 7 and 8.
Parity
Parity is the simplest way to check that transmitted data was received without errors.
The options are:
• None: no parity check is done.
• Space: the parity bit is always zero.
• Mark: the parity bit is always one.
• Odd: data bits plus the parity bit equals an odd number
• Even: data bits plus the parity bit equals an even number
“Space” and “Mark” are seldom used parity methods because they are less likely to
reveal the existence of a garbled bit. Using “Odd” or “Even” for parity is more com-
mon. If you want 2 stop bits (only 1 stop bit is supported in the hardware), you may
simulate it in software by choosing “Mark” for parity. This looks like an extra stop bit
in the data stream.
NOTE: Data bytes received with parity error are not transmitted to the peer.