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CHAPTER 4
The operating functions of the d15 modem are implemented in the base unit in which the d15 is integrated. The d15 is
a GSM900/1800/1900 Phase II+ device.
The corresponding functions are implemented conforming V.25ter, GSM07.07, and GSM07.05. Note that the
standards bodies regularly update these standards and so it can not be promised that the commands supported by the
d15 exactly conform to the latest versions of that specification. Some commands listed in these standards do not apply
in the GSM environment.
AT+C commands conforming to GSM07.07 and GSM07.05 and a number of manufacturers-specific AT commands
are available via the serial interface of the d15 for the implementation of the functionality.
Command input is via the operating functions of the base unit. The base unit translates the operating functions into AT
commands and the d15 executes the requested action.
The modem guidelines V.25ter is applicable in regards to the time sequence of interference commands. In accordance
with this guideline, commands start with the string AT and end with a carriage return (<CR> or 0x0D). Commands
are acknowledged with OK or ERROR . A command currently being processed will be interrupted by each
subsequent incoming character, so the next command must not be sent until the acknowledgment has been received
that command has been processed. Otherwise the current command will be cancelled.
4.1
Modem Communication Modes
The d15 modem supports the following communications modes:
4.2
Voice Communications
Analog Audio - Audio communications via a standard analog headset such as the headset used with the
StarTAC cellular phone. In this case the controls for answering calls, dialling, and hanging up are provided
by the AT command set interface. This mode would be used if the modem is being integrated into a
handheld terminal that will support voice communications.
Digital Audio - Digital audio is provided by the Motorola Proprietary DSC interface. This is used when an
external handset such as would be used in an automotive installation is used. In this case, the call controls
are provided on the handset. DSC handsets that support this interface are manufactured by and available
from Motorola. The AT command set can also be used to control calls. The DSC interface is a Motorola
proprietary feature that requires licensing from Motorola. Please contact your Motorola representative for
more information.
d15 Modem Integration and Application Developers Guide version draft 0.53
Software Interface
Page 43 of 181
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