iPAQ 5550 Audio adapter

This page describes the construction of an audio adapter for use with the iPAQ 5550 and a headphone/microphone combination designed to be plugged into a PC soundcard. For another very nice web page showing in pictures how to build such a cable see Vincenzo Ragone's article "Axim: in-out audio cable"

PC soundcard headphone/microphone

This figure shows a 3 pole 3.5mm (stereo) plug.
connection Headphone - plug (green) Microphone - plug (red)
TipLeft channelMicrophone
Ring1Right channelMicrophone (power)
SleeveGroundGround

iPAQ 5550 Audio Adaptor

This figure shows a 4 pole 3.5mm plug.
connection purpose wire color
TipLeft channelwhite
Ring1Right channelred
Ring2Microphoneblack
SleeveGroundshield

The above color codes are based on the use of a premade 4 conductor 3.5mm plug with 1.8m cable (ELFA part number 42-708-31; this is Marushin part MC-4350). This part is made by Marushin Electric Manufacturing of Japan.

The adaptor was made by attaching two 3.5mm stereo (i.e., tip, ring, sleeve) line sockets (i.e. jacks) in the following manner. (The jacks are ELFA part number 42-700-96; the orignal vendors part number is 133-1-8 "BW1118 World Peak".). Ideally one of these should actually be red (for the microphone), such as ELFA part number 42-700-70 - which is the same jack, but red in color, instead of black. The two connectors were connected using CEAM cabling systems LiYCY cable. You only need 1 conductor + shield (such as ELFA 55-778-12), but I happened to use (ELFA 55-778-38) which has four 0.14mm^2 conductors + shield - with an outside diameter of 4mm.

The jack for the headphones is connected as shown in the table below. Note that Tip is the coppor colored connector on this jack.
A connection was made to carry the microphone (black) to a wire to the other jack (via the yellow wire). A second connection is made by connecting the shields of both cables to provide a ground.

connection purpose wire color
TipLeft channelwhite
Ring1Right channelred
SleeveGroundshield

The jack for the microphone is connected as shown in the table below. Thus both tip and ring were connected to a wire (I chose yellow). Note: You can't use a mono jack, as the plug's ring would be connected to the sleeve contact of the jack - this the external microphone would not be used.

connection purpose wire color
TipMicrophoneyellow
Ring1Microphone (power)yellow
SleeveGroundshield

A sample wiring diagram is shown below:

This figure shows a simple wiring diagram.

Details of how the iPAQ can detect if a microphone is connected or not and how the external microphone is powered can be found in the data sheet (pg. 26) of the data sheet for Asahi Kasei AK4535.


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Latest update 29 May 2006
© 2004, 2005,2006 G. Q. Maguire Jr., KTH/IMIT

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