Installation Instruction
Ref : SCT TMO MOD SPEC 662
Rev.: B
Ref. sec. :
Date:
18/11/2004
Document
. All rights of reproduction and disclosure reserved.
MO2XX module – Confidential under NDA
Page 20/67
3.9 POWER MANAGEMENT
3.9.1 Interface identification and diagrams.
On an external point of view (i.e. as seen by a DTE), the MO2XX has 4 different states:
•
OFF:
In this state, none of the MO2XX functionality are running (the serial link is switched off)
•
ON Sleep:
In this state, the MO2XX is asleep and the external serial link is switched off. Any interrupt will wake the
module up as well as the external serial link. An interrupt can be generated by reception of a character
but it is lost.
NB: in this state, the module is attached to the GSM network.
•
ON Active:
In this state, the MO2XX is switched on and the serial link is activated. The MO2XX is able to receive
correctly the data sent by the DTE.
NB: in this state, the module is attached to the GSM network.
•
Reset:
This state indicates that the MO2XX is in its setup procedure and implies that the serial link is
deactivated.
3.9.2 Recommended strategy : software management
A software management of the power consumption can be handled via the GSM 07.10 protocol.
Other strategies are possible and they are developed in the Annex 2.
3.10 DATA / COMMAND MULTIPLEXING
The serial link between the DCE and a DTE (PDA, phone,…) is used to send two different kinds of data
flow: AT commands and PPP data packets. these two flows cannot be mixed together (not enough
bandwidth). So, this serial link can be used in two different exclusive modes:
- Command Mode: The serial link is reserved for the AT Commands flow
- Data Mode: The serial link is reserved for the data flow
But, during a data connection, the modem or the DTE may need to send some AT Commands to notify the
other side of a major event. As there is just one serial link to send these two kinds of data, it is necessary
to have a special procedure to switch from one kind to the other.
•
The first solution provided by the GSM standard is to use +++ and ATO. This solution very simple to
implement, has the main drawback to allow only the DTE to control the switch between the 2 modes and it is
usually only used to hang up a data call.