VEGA INSYS Modem GPRS 5.0 - Manual (Page 108)

Connections, Display and Control Elements INSYS GPRS 5.0 serial
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13.3 Internal Design
For the INSYS GPRS 5.0 serial, a µcontroller is placed in series between the external
serial interface and the GSM/GPRS engine.
All commands sent to the INSYS GPRS 5.0 serial via the serial interface are first re-
ceived and evaluated by the µcontroller.
If the command results in just one action by the µcontroller, the response to the
application (e.g. OK) is created directly by the µcontroller.
If the GSM/GPRS engine is activated while commands are entered, the response to
the application is determined by the engine; in this case, the µcontroller will just
relay them.
During CSD calls or standard GPRS connections the
µ controller relays the data
transparently in both directions.
When using the integrated TCP/IP stacks (TCP transparent) of the
µ controller, the
data from the
µ
controller is packed into the according protocol elements, sent via
the GSM/GPRS engine and vice versa.
The peri odically perfor me d statu s quer ies (AT**GSMREQ) an d eva luation s of incoming S MS occur internally on another interface ; they will n ot have an effect on the communicati on bet ween the a pplicati on and the {{{PRO DUCT DESCRI PTION}}}.