Transcript: If you are looking to connect an iPod, MP3 player or other mobile music device to your marine stereo there are several ways to do it. Each has it's pros and cons and things to consider.
A new marine stereo will have at least one auxiliary input for patching in the audio from an external device. There will be either a 3.5 mm plug on the faceplate like this, or RCA jacks on the back that look like this. You will notice that the 3.5 mm plug looks a lot like the headphone jack on your device. To connect your device you will need a cable like this one. Plug one end in here and the other end in here. Switch your stereo to Auxiliary mode and anything you play on your device will play through the stereo.
Many waterproof stereos don't have the plug on the front because it is an avenue for water to get into the unit. Instead they will have these RCA jacks on the back. You will need an adapter like this one. You connect the RCA plugs, and then you can mount this end of the adapter in a convenient place. As you can see, it provides this handy waterproof cover. Then you connect your device using the headphone jack, just like we did before.
The advantage of making a connection this way is that you control your iPod or MP3 player using the interface you are familiar with. On the down side, your device will not be recharged and you can't use your stereo remote control to make any adjustments other than to change the volume.
iPods and iPhones are, by far, the most popular music devices and many stereos will allow you to connect using a special cable that has a 30 pin iPod plug on one end, like this one. These cables usually plug into the back of the stereo, so when you do the install, you will want to run the cable to a glove box or another convenient location to store your device. An iPod connected this way will be recharged, but you actually control the unit from the faceplate of the stereo. Or you can use the stereo's remote, if it has one.
The down side to this type of connection is that the control interface will be different than what you are used to, because you will be controlling it through the stereo. In some cases the interface may not offer all of the features that your device does like internet streaming.
Many stereos also offer a USB port for connecting a device like an MP3 player, flash drive or memory stick. An MP3 player connected via USB like this will be recharged. iPods can sometimes be connected via USB also, but not all stereos have the compatible Apple software needed to control an iPod. However, you might be able to recharge your iPod using the USB connection while at the same time you play your music using the auxiliary port like we described earlier.
Some stereos have the USB port on the back and you will need a USB extension like this one that allows you to mount a convenient plug, similar to the audio adapter we used earlier.
Lastly, some stereos have an iPod or MP3 player dock right inside instead of a CD player. This gives you a handy place to store your device where it can be protected from the weather, and all of the connections you need are right inside the dock.