Installation Instruction

Ref : SCT TMO MOD SPEC 662
Rev.: B
Ref. sec. :
Date:
18/11/2004
Document
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. All rights of reproduction and disclosure reserved.
MO2XX module – Confidential under NDA
Page 66/67
Remarks:
•
DTE_ESCAPE_CMD
=
MOD_ESCAPE_CMD
= {0x18,0x7E,0xDB,0xFF}, this string could be change by
AT command in the future.
•
These two strings are the effective separation between the data flow and the command flow
2
nd
case
: the modem requests the DTE to go in the suspended data mode
1. The modem indicates the request by moving
DTE_ESCAPE_CMD
.
2. The DTE indicates the order by moving
MOD_ESCAPE*_CMD
and then begins to search in the data flow the
MOD_ESCAPE_STR
from the modem.
3. When the modem is ready, it sends the
MOD_ESCAPE_STR
string and it wait for
DTE_ESCAPE_STR
.
4. When receiving this string, the DTE then move back
MOD_ESCAPE*_CMD
and sends the
DTE_ESCAPE_STR
, which indicates to the modem every byte after that must be considered as part as an AT
Command
Modem Tx
DTE_ESCAPE_CMD
DTE Tx
MOD_ESCAPE_CMD
MOD_ESCAPE_STR
DATA
DATA
DTE_ESCAPE_STR
COMMAND
COMMAND
Wait for
DTE_ESCAPE_STR
1.2.6. Transition (3): Suspended Data -> Data Mode
This transition is always ordered by the PDA via the classical ATO command.
The SB acknowledges with the CONNECT message
Modem Tx
DTE Tx
DATA
COMMAND
ATO
DATA
COMMAND
CONNECT:9600
1.2.7. Transition (4): Suspended Data -> Command Mode
The theoretical transition is Data to Command and happens to end a data connection; the
Suspended Data Mode is just a temporary transition between the two.
The real procedure is Data to Suspended Data (already detailed in transition 2) and then Suspended Data
to Command Mode.
There are two different cases:
•
Or the distant can hang up and then the modem is going to send a “NO CARRIER” message
Modem Tx
COMMAND
NO CARRIER
COMMAND
Suspended data mode
Command mode
•
Or the DTE wants to hang up and then an ATH is sent and the transition has to be made on the answer
to this command (OK)