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b) A time of greater than 33 bit transmissions (at current baud rate) must have
elapsed since the last erroneous message
At the end of a frame:
a) Checksum is correct
b) A STOP character must be present.
During a frame:
a) Framing error
b) Overrun error
c) Character parity (if enabled)
d) Character time-out
e) Receive Buffer overflow
f) Message is too long
7.3 Message time-out
The KITZ unit uses timers to speed-up re-initialisation of message reception and
transmission when a message timing error occurs (on the K-Bus or IEC-870 port).
7.3.1 K-Bus timers
The received K-Bus message is checked for character gaps. The timer value is
2ms between characters.
The transmitted K-Bus message cannot take greater than 500ms to transmit.
7.3.2 RS232 (IEC-870) timers
These timer values are dependent on the data rate used (the data rate switch
position determines the timer value used).
The received IEC-870 message is checked for character gaps within the
message. The maximum gap allowable is 33 bits (at current data rate).
The transmitted IEC-870 message is not allowed to take greater than a
5,500 bit time period (at current data rate) to transmit.
Note: IEC-870 - 5 FT1.2 states that data transmitted in this format should not
have inter-character gaps. The KITZ unit transmits using this format, but
the receiver allows gaps as mentioned above. The 3 byte (33 bit) delay
after message error is adhered to.
7.4 Conversion sequences
When a valid message is received on one channel (either K-Bus or IEC-870),
the following operation occurs:
(1) the other channels receiver is disabled.
(2) the message is converted (IEC-870 to K-Bus or K-Bus to IEC-870).
(3) the message is transmitted on the other channel.
(4) the other channels receiver is re-enabled.
7.5 Receive message buffering
Under normal operating conditions the KITZ unit will not need to buffer received
messages because the master station will send a message and then wait for a
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