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NUUKIAWORLD FBUS & MBUS

NuukiaWorld project:
FBUS & MBUS adapters

2. General information


2.1 Overview

In the following chapters several ready-to-use examples of FBUS & MBUS adapters are shown. The circuits has been developed to be as simple as possible without trade-off with the reliability and safety.


2.2 Required competence


WARNING! Although the author has tested these circuits, no guarantee can be given for the operation or compatibility. Building and connecting devices to electronic appliances contains always a risk to damage the equipment seriously. Electrostatic discharge can damage the devices without any visible handling mistake.

If you do not understand the purpose of a single component in these circuits, do not build these devices. You are doing everything at your own risk. The NuukiaWorld has no resources and interest to answer questions about your non-working adapters. Questions like "I built your adapter, but it does work. What to do?" where very common during the previous version, and they are naturally impossible to answer even for a professional designer. In short: no questions will be answered.

You must be so familiar with electronic designs that you can solve the possible problems in the circuit by yourself. The FBUS & MBUS communication faults can be searched by comparing the signals with the oscilloscope images shown in chapter 1. Remember that there is always a risk of connecting the ±12-volt RS 232 signals to the sensitive phone inputs. Before connecting the adapter to the phone for testing, test the functions of the power supply and voltage separation carefully.


2.3 Serial port pin arrangement

These designs are intended to use a separate RS 232 cable for DB9 connectors. This cable must be intended to be used between DTE and DCE. A null-modem cable (DTE - DTE) cannot be used. The pin numbers are shown in table 2.1. Please note that if you are going to use a serial port with DB25 connector, the RS 232 circuits are on different pins.

Table 2.1 RS 232 circuits on DB25 connector (compared to DB9)
V.24 Circuit DB9 pin DB25 pin
102 GND 5 7
103 TxD 3 2
104 RxD 2 3
 105 RTS  7  4
 108/2 DTR  4  20
109 DCD 1 8


2.4 Nokia 5100/6100 series connector

The adapter designs shown in the following chapters can be used with all Nokia phones supporting the corresponding buses. You must find out the pin arrangement of your phone by yourself. Because using with the Nokia 5100/6100 series phones is the most common case, the pin arrangement is shown in figure 2.1 and table 2.2.

Table 2.2 The pin outs of the Nokia 5100/6100 series GSM phones.
Pin 1 2 3 4 5 6 7 8 9
Signal Vin PWM XMIC Signal GND XEAR MBUS FBUS RX FBUS TX Logic GND

Figure 2.1 The pin outs of the Nokia 5100/6100 series GSM phones.

There are no Nokia connectors for sale. You must try to build some kind of connector by yourself, or buy an inexpensive third-party headset with an openable connector. Check that connector can be opened with a screwdriver etc. They usually contain all pins, so the buses can be connected with it. But this cannot be guaranteed.


2.5 Nokia 3210 connector

NuukiaWorld has usually designed and published only circuits that have been useful for the author himself. The NuukiaWorld author has only one mobile phone, Nokia 6110. This is the reason for that the base instructions are only for Nokia 5110/6110 series.

But now here are two exceptions. The first one: The pin outs for Nokia 3210 in figure 2.2 and table 2.3. The golden bus contacts are under the back cover of the phone.


CAUTION! Please note that NuukiaWorld has not tested this pin out and it is functionality, it is based on third party information. All NuukiaWorld adapters have been reported to work fine with Nokia 3210. The Nokia 3210 phone has limited functions. Even all FBUS-based applications and their functions do not work with it.

Table 2.3 The pin outs of a Nokia 3210 GSM phone.
Pin 1 2 3 4 5 6
Signal BTEMP FBUS TX GND MBUS FBUS RX VPP

Picture 2.1 The back cover of a Nokia 3210 has been removed to expose the bus contacts near the battery slot.

There is no ready solution for connecting the adapter to a Nokia 3210. Even small breaks is the contact will cause problems in the communication. One solution is to cut a piece of a rubber eraser and mount the bus wires through it. This has been reported by Jari-Pekka Korhonen (http://koti.welho.com/jkorhon2/3210/).

Figure 2.2 The pin outs of a Nokia 3210 GSM phone.


2.6 Nokia 3110/8110 series connector

The pin outs for Nokia 3110/8110 series phones are shown in figure 2.3 and table 2.4.


CAUTION! Please note that NuukiaWorld has not tested this pin out and it is functionality, it is based on third party information. The NuukiaWorld FBUS adapter has been reported to work fine with Nokia 3110, 8110, and 8148.

Table 2.4 The pin outs of a Nokia 3110/8110 series GSM phone.
Pin 6 5 4 3 2 1
Signal MBUS FBUS TX EXT_RF XMIC V_OUT GND
Signal V_IN FBUS RX HOOK XEAR SGND BENA
Pin 12 11 10 9 8 7

Figure 2.3 The pin outs of a Nokia 3110/8110 series GSM phone.


- © Copyright 1998, 1999, 2000, 2001 Panu M Tuominen. All rights reserved. Republishing this document partially or completely is forbidden. Internet hyperlinks to the main page are allowed and such linking is encouraged. Please read the FAQ page carefully. You are doing everything at your own risk. See the WARNING! above.

For example, Nokia 5110 and Nokia 6110 are 5100/6100 series phones. The tests have been done with Nokia Data Suite 2.0, Nokia Logo Express, LogoManager demo version, and a Nokia 6110.

21.5.2001 - nuukiaworld@gmail.com
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