
APPENDIX
Protocol Data Mode
92
2.10
•
19.01.2007
FT-side host
FT
HD
LC
LU2
PT 1
LU2
LAP
PT-side host 1
RS 232
RS 232
DECT
PT 2
LU2
LAP
PT-side host 2
RS 232
PT 3
LU2
LAP
PT-side host 3
RS 232
PT 4
LU2
LAP
RS 232
LU2
LU2
LU2
DECT
DECT
DECT
LA
P
CO
M
M
A
N
D
HD
LC
LA
P
CO
M
M
A
N
D
LAP 1
LAP 2
LAP 3
LAP 4
PT-side host 4
Figure 6: Distribution of LU3 in protocol data mode
For the transport of LAP frames over the RS-232 interface a HDLC style framing is used.
The HDLC layer also serves the purpose of multiplexing and de-multiplexing LAP channels.
The protocol data mode includes a command channel. It is used for call control and provides
mechanisms for future extended control functions.