Nokia Mobile Phones NSE-5 Series, Service Manual, Page: 269 / 327

PAMS
Technical Documentation
HFU–2 Handsfree Unit
Page 3
Original 11/97
Introduction
The HFU–2 is a handsfree unit for DCT3 compatible handportable
phones. It provides rapid charging for the phone, a possibility to use HF–
operation and connections to the data–card and handset unit. The HF
box can be connected directly to the Mobile holder MCC–1 via the exter-
nal cable.
Technical Summary
The HFU–2 has connections to car battery, car ignition sense, car radio
muting, antenna motor control, data–card, handset HSU–1, external
speaker and microphone. The unit has a System–connector that pro-
vides an interface to the Mobile holder MCC–1 via the external cable.
The unit consists of a rapid charger, HF–microphone– and speaker ampli-
fiers, interface to handset, – datacard and –phone, voltage regulators and
control circuit (microprocessor).
The HFU–2 is always connected to the car battery. To save the car bat-
tery, HFU–2 goes in to the sleep mode if the car is not running and/or the
phone is not connected.