Nokia 6020b Service Manual

 RM-31

Nokia Customer Care

7 - System Module

34

COMPANY CONFIDENTIAL

Issue 1 03/2005

Copyright © 2005 Nokia. All Rights Reserved.

ACI (Accessory Control Interface) is a point-to-point, Master-Slave, bi-directional serial bus. 
ACI has two main features: 

• The identification of accessory type is provided 

• The insertion and removal detection of an accessory device 

• Acting as a data bus, intended mainly for control purposes.

FBUS is an asynchronous data bus having separate TX and RX signals. Default bit rate of the 
bus is 115.2 Kbit/s. FBUS is mainly used for controlling the phone in the interface to PC via 
DKU-5. 

The VOUT pin delivers the power supply for PopPort

TM

 accessories, which are using the ACI 

or FBUS. The voltage level is 2.78V / 70mA.

1

VCHAR

2

GND

Charge ground

3

ACI

Insertion & removal detection /
Serial data bi-directional 1 kbit/s 

4

Vout

Power supply for external accessories

5

Not used in RM-31

6

FBUS_RX

Serial data from accessory to phone /
115 kbit/s

7

FBUS_TX

Serial data from phone to accessory /
115 kbit/s

8

GND

Data ground

9

XMIC N

Negative audio in signal

10

XMIC P

Positive audio in signal 

11

HSEAR N

Negative audio out signal.

12

HSEAR P

Positive audio out signal.

13

HSEAR RN

Negative audio out signal.

14

HSEAR RP

Positive audio out signal.