User Guide

RH-37
System Module Nokia Customer Care
Page 38 Nokia Corporation Issue 1 07/04
Table 12: System connector interface description
ACI
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
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
Pin # Signal Notes
1VCHAR
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 RH-37
6 FBUS_RX Serial data from accessory to phone /
115 kb it /s
7 FBUS_TX Serial data from phone to accessory /
115 kb it /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 RN Double mono in RH-37
13 HSEAR P Positive audio out signal.
14 HSEAR RP Double mono in RH-37