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Use iPhone as a speaker phone in the car iOS devices
Something that maybe not everyone has thought about with the iPhone is that the microphone is good enough to use in conjunction with an FM transmitter in the car as a speaker phone. This is a cheap and secure way to drive and speak at the same time.

The quality of the sound for the receiving part may not be the best, but it's good enough and it's better than using a headset. It even stops the music when the phone rings, such as a good installation of a phone kit for a car will do when receiving a call.
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Use iPhone as a speaker phone in the car
Authored by: ekerkhoff on Jul 28, '08 08:18:02AM

How is it secure when you are broadcasting the conversation over FM waves that allow anyone within range to tune-in?

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Use iPhone as a speaker phone in the car
Authored by: hamarkus on Jul 28, '08 09:53:43AM

Can't much worse than talking on a cell phone in any public environment. But I am curious whether only the voice of person calling the iPhone is broadcast or both voices?

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Use iPhone as a speaker phone in the car
Authored by: soltmann on Jul 28, '08 08:24:14AM

Even better, if your car has a cassette player, is to use a cassette adapter. The sound quality is much better and you don't have to fiddle with tuning in the radio.

To use a cassette adapter with the original iPhone you will have to remove approx. 1/8" to 5/32" of the insulation that covers the mini-jack (or buy an inexpensive iPhone headset adapter). I find removing the insulation pretty easy. Just lay the mini-plug on a hard counter. Take a knife edge (anything sharper than a butter knife will do) and place it perpendicular to the mini-jack at the spot you want to cut. Using the knife edge roll the mini-jack back and forth across the table top slowly increasing pressure. Stop when you have penetrated the insulation but before you hit metal. Grab the portion you want to remove with a plier and twist -- the insulation should come off at the score line.

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Use iPhone as a speaker phone in the car
Authored by: tofergregg on Jul 28, '08 08:39:45AM

I thought this would be a great way to go, but there is tremendous feedback and the echo for people you're talking to is unbearable. Maybe I have it set up wrong, but that's what happened when I tried it.

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Use iPhone as a speaker phone in the car
Authored by: milkmage on Jul 28, '08 08:42:13AM

you talking about your music FM transmistter? does that even work? I figure the music playback (therefore the output) is suspended when you switch to phone mode.

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Use iPhone as a speaker phone in the car
Authored by: hamarkus on Jul 28, '08 09:50:58AM

The FM transmitter takes whatever comes out of the headphone jack. And the iPhone will send the call to the headphone jack when something is in the headphone jack.

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This is bogus
Authored by: Lectrick on Jul 28, '08 09:48:26AM

If you REALLY want to do speakerphone in the car, look no further than the Contour Surface Sound Compact Car Kit. You can get it in Apple's stores (online or brick and mortar) or perhaps on amazon. Absolutely awesome. 5/5 star product IMHO. Yes, it is $99 however.

In /dev/null, no one can hear you scream

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Use iPhone as a speaker phone in the car
Authored by: dr_photo on Jul 28, '08 10:39:29AM

This must only work for some iPhones because I have tried this several times (even prior to seeing this hint) and it has not worked for me. I have a 4Gb iPhone and while I do get an incoming call (and the ring over the FM transmitter), as soon as I pick up I get none of the call audio. A soon as I unplug the FM transmitter from the iPhone though the call functions as normal through the ear piece.

It might have to do with the fact that I have an adaptor to make the FM transmitter fit in the headphone port, but that shouldn't make a difference.

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Use iPhone as a speaker phone in the car
Authored by: scottrussell on Jul 28, '08 02:22:38PM

I agree. I frequently listen to my iPhone in my car through my stereo's aux input. An incoming call rings through the car speakers, but when I click "answer" on the phone, no audio is transmitted to the stereo.

I must unplug the audio cable in order to take the call. I'm just not sure why this tip works for some iPhone users, but not all. Weird.

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Use iPhone as a speaker phone in the car
Authored by: u2mr2os2 on Jul 28, '08 05:27:38PM

It would work for me. The thing is to understand what the iPhone does so that you can debug what's going on.

If you have a Bluetooth headset connected to the iPhone, the iPhone will route the call to that first. So, if you want to use the FM transmitter for call audio, you should turn off the headset. This is also why I've been put into the FM transmitter speakerphone mode inadvertently, because my BT headset was off or had become unconnected.

The iPhone will route call audio through the headphone jack if connected rather than the built-in earpiece. This is what happens with the headset that comes with it. However, that headset also has a mic and a 4 conductor plug to go with it. When a 4 conductor connector is plugged into the headphone port, the iPhone routes both the speaker and mic audio to the headset. Your FM transmitter and ordinary headphones without a mic only have a 3 conductor plug. If a 3 conductor plug is in the headphone jack, the iPhone will only route the call speaker through the connector and use the iPhone's built-in mic to pick up your voice.

Another problem that can cause you to not hear the caller's audio even if your FM transmitter setup is working is the half-duplex speakerphone effect. If your iPhone's mic picks up enough sound, it will send that audio, but mute the caller's audio to avoid picking that up and resending it as well, creating feedback. The problem is that as long as your mic is picking up sound, it will keep the caller's sound muted. You may have been on the other end of this sometime where you couldn't seem to be heard by the other person who had you on speakerphone, but had noise on their end, keeping your audio muted.

I think the iPhone goes into a speakerphone mode when the earpiece audio is going out the headphone jack and it is using the built-in mic. It doesn't when both go out the headphone jack as with the headset it comes with. Of course, this situation is easy to come by in a noisy car cabin, but could also explain why not everyone has the problem (they might have a quiet car).

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