User's Manual

APPLICANT: MOTOROLA, INC. FCC ID: IHDT6AC1
Exhibit 8
43
5.2.1 Digital audio.
In case of digital audio channel a DCS drives is in used. The
consideration that should be taken in this case is to be aware
of the present of the hook switch. The hook switch will
destinguish if the handset is In/Out of use.
There are two DSC bus accessories for audio defined for the
D15:
External Handset.
DHFA - Car Kit for Hands Free.
5.2.2 Analog Audio without Handsfree.
The D15 will drive the audio out/in in order to allowed a
voice call. In order to connect an Headset it is needed to
amplified the speaker and microphone channels.
An example for these drivers can be seen in Apendix ?? EV
board.
Other point to be taken in consideration is the Buzz noise
existing in GSM phones due to the transmission rate (217Hz).In
order to minimize this noise the D15 have a separate ground
for the analog circuits.
Analog
Circuits
Logic
Circuits
PS
Digital Ground
Digital Ground
Analog
Ground
Customer side
D15