Technical data

Description of the parameters in the header
com_class: 1 byte, format: KH
FDL request =00
H
in transmit buffer:
Service request to layer 2
FDL confirmation=01
H
in receive buffer:
Acknowledgment from layer 2 after FDL request
FDL indication =02
H
in receive buffer:
Indicates that the data was received.
user_id: 1 byte, format: KH
Freely assignable ID which is returned unchanged with
a confirmation. In an indication the value is "0". With the
user_id it is possible to establish a unique assignment
between request and confirmation.
com_class
user_id
service_code
link_status
Byte
1
2
3
4
0
Header
service_class
DSAP/RSAP
rem_add_station
rem_add_segment
Data
5
6
7
8
249
Fig. 8.1 Structure of the Header with a Job Buffer to be Sent/Received
B8976060/02 Free Layer 2 Communication
8 - 5 Volume 1