Here's a simple guide to making ur own DKU-2 cable for nokia.I've made one for my nokia 3230 and is working great
the schematic of the DKU-2 cable is given in the picture attached below.
it is clear that it is simply 4 wires connected from the usb port to ur phone's POP PORT. The POP PORT consists of 14 pins, the pop port connector contains pins from 2 to 14.
on the connector u can short pins 2 & 3 or solder a diode between them to tell the phone that u've connected an accessory to it, but u can also do without it, it is not at all necessary. it is required when u make a handsfree set.
Pop port pin numbers 5,6,7,8 are used to connect the phone to the usb port as shown in the schematic. no additional circuitry is employed between the phone and usb port coz it is a true usb cable.
DKU-5 uses a complex circuit between phone & USB coz it's not a usb cable although we plug it into a usb port. it contains a serial to usb converter which takes serial data from phone and sends it to usb port via usb-serial converter. it has to make a virtual COM port on ur computer.
the schematic also shows u how to make a stereo handsfree set. in reality it won't be stereo but dual mono bcoz for stereo nokia uses a proprietry chip in their handsfree to tell the phone that it's a genuine handsfree set.
MIC's -&+ pins are connected to pins 9&10. u also need to connect a mini push button switch parallel to the mic to answer or end a call.
left and right speakers are connected to pins 11, 12, 13, 14.
although knowledge of electronics is not essential for this but it would certainly make ur task easier.
a brief summary of components required:
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1: usb connector ( better if u get it with a cable or buy a 4 core cable separately)
2: POP PORT Connector ( try if u can get it from market or do as i did. i took it out of a non functional DKU-5 Cable from my friend)
3: Soldering kit (iron, wire & flux.)
4: Diode 1N4001 (optional)
now u can guess what should be the price of a dku-2 cable coz it contains absolutely nothing in terms of electronics. 3,00 Euros must now be a ridiculously high price for simply a usb and pop port connector with just a cable in between.
i was using an IrDA before this but bcoz of its slow speed i had to move to a usb cable. this cable gives me transfer rates of 460800 bps while IrDA was limited to 115200 bps in normal mode.
