Nokia Mobile Phones NSE-5 Series, Service Manual, Page: 270 / 327

PAMS
Technical Documentation
HFU–2 Handsfree Unit
Page 4
Original 11/97
List of Modules
Name of module Type code Material
code
Notes
HF unit HFU–2 0694049 Advanced handsfree unit
HF module ED2 0200948 ED2 Advanced hadsfree module
Assembly parts MHFU–2 0261602 Mechanical Parts
Operation
Phone not connected (sleep mode):
When the phone is not connected the current consumption of
the device has been minimized. The switching mode power
supply (SMPS) and audio circuits has been turned off. HFU–2
is only waiting a phone to be connected.
Phone connected (active mode):
When the phone is connected to the HFU–2 it goes into the ac-
tive mode. In the active mode the device provides charging
current to the phone. It also can provide hands free call option
using the external speaker and the external microphone or
micspeaker unit. If more private call wants to be made, the
phone itself can be used as a handset without losing the exter-
nal antenna connection or with handset (option).
The phone controls all functions of HFU–2. In the active mode
the HFU–2 sends all state transitions to phone via mbus.
HFU–2 also provides car radio mute function during call.
HFU–2 can control the mobile antenna motor if it is installed to
the car.
Supply Voltage and Power Consumption
Conn. / pin Line Symbol Minimum Typical /
Nominal Maximum Unit / Notes
X300 / 6 GND 0 VDC
X300 / 1 VB 8.0 16 VDC (working)
X300 / 1 VB 10.8 13.5 16 VDC (spec. fulfill)
X300 / 1 VB 0.05 1 2 IDC/A (operating)
X300 / 1 VB 0.2 0.8 1 IDC/mA (sleep
mode)