Glossary
MECip
SECURE
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Group Communication
Object
Group communication objects contain the datapoints which
are transmitted via runtime communication. One or more
group addresses are assigned to one group communication
object. One of these assigned group addresses is the sending
group address (to send the group communication object
value to the bus). The remaining assigned group addresses, if
available, then receive the value.
Group Object
same as Group Communication Object. A data point in KNX
can be called shortly a 'Group Object' or just 'Object'.
Group Telegram
Group-oriented telegrams are named Group Telegrams.
Filtering of Group Telegrams by couplers is accomplished
according to their built-in filter tables for group
communication.
IACK
see Acknowledgement frames
Individual Address
The Individual Address of a device defines the location of the
device within the topology.
Long Telegrams
Long telegrams or long frames are telegrams having an
APDU length that exceeds 15 octets. Long telegrams use the
extended frame format.
NACK
A NACK is a negative IACK frame. When the sender detects a
NACK, then the sender´s data has not been received correctly
by at least one device meaning it has not been successfully
transmitted to one or more receivers. Thereafter, the sender
waits for a short time period and retries to send the frame.
Physical Address
same as Individual Address
Physical Telegram
Individually addressed telegrams are named Physical
Telegrams.
Repetition of telegrams
When there is no positive IACK on the regarded TP line (e.g.
NACK, BUSY, missing IACK), couplers usually repeat messages
up to three times. For all MEC couplers, the number of
repetitions on TP is configurable.
