Siemens Mux_guide_v06 - Manual (Page 32)

Multiplexer User's Guide
Confidential / Released
s
m
o b i l e
Mux_guide_v06 Page 32 of 36 30.06.2004
4.4 Example: Establishing logical channels without parameter
negotiation
• Send AT+CMUX=0; wait for the response
• Send Request SABM for DLCI = 0; wait for the response
• Send Request SABM for all requested DLCIs; wait for the response
As a result the multiplexer is established and information / data can be transmitted
(
⇒ ready for Information Transfer).
Customer
µC
Closed Down Closed Down
RequestStartUp
ResponseStartUp
ConfirmStartUp
IndicationStartUp
Disconnected Disconnected
Serial
interface
Sta
rt
U
p
"A
T+CM
UX"
Connected
DLCI = 0
D
LC
Es
tab
lis
hm
en
t,
Cr
eat
e D
LCI =
0
Disconnected
DLCI = 0
Disconnected
DLCI = 0
RequestSABM
DLCI = 0
IndicationSABM
DLCI = 0
ResponseUA
DLCI = 0 ConfirmUA
DLCI = 0
Connected
DLCI = 0
Connected
DLCI = 1
D
LC
Es
tab
lis
hm
en
t,
Cr
ea
te
D
LCI
= 1
Disconnected
DLCI = 1
Disconnected
DLCI = 1
RequestSABM
DLCI = 1
IndicationSABM
DLCI = 1
ResponseUA
DLCI = 1 ConfirmUA
DLCI = 1
Connected
DLCI = 1
GSM engine µC
Figure 13: Establishing the multiplexer control channel and the logical channel