Silicon Laboratories SI2493/57/34/15/04 - Manual (Page 241)

AN93
Rev. 1.3 241
For Figure 39, assume that the originating modem transmits first and that the two modems alternate transmitting
and receiving. For simplicity, this figure does not show the provisions for timeout cases.
Figure 39. SMS Process in Host and Modem
Orig ina te
?
AT+FCLASS = 2 56
(V.2 3 h alf -du ple x )
ATD Txxxx ; ATDT ;
O A
AT +FRM =2 00
Pr otocol
?
AT+FTM = 20 1 AT+FTM =202
1 2
Da ta recei ved
from Host
?
N
Data re ceive d
fro m Ho st
?
N
80 bi ts of ma rk
Ho st sen ds
messa ge fol low ed
by 15 0 ms o f
si len ce , then ESC
Y
8 0 b its of mark
Host send s
messag e fo ll owe d
by 15 0 ms of
sil en ce , th en ESC
30 0 bits chan nel
se izure
( altern atin g 1 's &
0 's)
Y
ESC to
Co mmand
Mod e
?
Se nd Ma rks
N
CONN ECT n
n = 1 o r 2
ESC to
Co mma nd
Mo de
?
Sen d Marks
N
Y
R ecei ve messag e ,
send to Ho st
Y
OK OK
OK
Implicit +FRM
CONN ECT CONNEC T
H ES = 1