iPhone hearing aid t-coil (telecoil) compatibility and clicking noises
We happily received our new Verizon iPhone4 a week ago, but, with considerable disappointment, sent it back yesterday ...
This iPhone did not work with the t-coil on my wife's hearing aids. This subject has been discussed previously in these discussion groups, but suggestions like using TTY or adding bluetooth dongles to the hearing aids are simply not acceptable.
Here are some details ...
My wife wears two Oticon Synchro P hearing aids. They are about 4 years old. They are expensive hearing aids. They have a t-coil setting which she normally uses with telephones, and it works quite well with our Uniden land line phones and our old LG cell phones. The purpose of the t-coil is to inductively couple a telephone or other device to the hearing aid, rather than depending on acoustic coupling which often results in poor sound quality or lots of feedback. With my wife's hearing aids, when turned on, the t-coil does pick up some noise, more like a hum than white noise, but at an acceptable level. When we first tried the iPhone, just placing the iPhone speaker next to the ear with hearing aid with t-coil enabled, caused the noise/hum level to increase noticeably, to a level that was only marginally acceptable. There were other issues, as well.
Except for the noise increase, it did not seem to matter if the t-coil was turned on or off, i.e. there did not seem to be any inductive coupling through the t-coil. Essentially the coupling was acoustic, resulting in poor sound quality.
Last but certainly not least, we also got a loud clicking noise. Once again this was when the iPhone was next to the ear with the hearing aid with t-coil enabled. The noise sounds like a relay clicking, at a rate just slightly faster than I could count. This only occurred in the house, and was gone when we attempted to demonstrate the problem at a Verizon store. I took the iPhone back home determined to find the source of the clicking interference by turning off all the wireless phones and other electronics in the house. When I turned off my Linksys router, an old WRK54G model, the clicks went away. Okay, so I turned the router back on, and turned WIFI off on the iPhone - sure enough, no clicks. And there were no clicks when the t-coil was turned off, or when the iPhone was not in close proximity to the hearing aid (with or without WIFI enabled). So there is a interaction between the WIFI signal, the hearing aid t-coil, and the iPhone in combination.
Next, I tried changing the WIFI wireless channel on the router from channel 1 (2.417 Ghz), to channel 6 (2.442 Ghz), to channel 11 (2.467 Ghz) .. none of this helped, i.e. if WIFI was enabled on the iPhone, and the iPhone was near the hearing aid with t-coil enabled, the clicks were there and very loud.
Next, I looked at some of the router parameters, and noticed that the router sends a short preamble at a default interval of 100 msecs (10 per second) - roughly my guess of the click frequency. Changing this interval to 1000 msec (1 per second) did indeed change the frequency of the clicks to 1 per second!
My theory on this is that we were hearing all the WIFI packets, but most of it sounded like noise, and only the periodic preamble broadcasts were identifiable as clicks. Strange, eh ?
So what now ? Turn off WIFI on the iPhone? No. Change the preamble frequency permanently ? Probably not since I have no clue as to what effect that might have on the various WIFI devices that are used around here. Buy a different router ? Well, maybe, but the iPhone4 only supports 802.11 b/g/n on 2.4Ghz, so it's a toss-up whether or not a newer router would help. Buy new bluetooth hearing aids ? Not anytime soon. Buy the bluetooth add-on gizmo ? Probably not ... Few hearing impaired people really want all that hardware - they just want their t-coils to work.
In the end, we didn't try another unit ... we simply gave up and sent the iPhone back. Since we really like the iPhone, we'll wait until the iPhone5 comes out, try that, and if it doesn't work, we'll find an Android phone from LG or some other manufacturer that does work.
PS
Apple says the iPhone4 CDMA has an M4,T4 (i.e. very good) rating for hearing aid compatibility, "Based on testing conducted by an independent laboratory following the ANSI standard C63.19, "American National Standard for Methods of Measurement of Compatibility between Wireless Communications Devices and Hearing Aids."" I think Apple needs to find a different lab, or do in-house testing of the top 10 hearing aids. A very large group of potential customers would appreciate it.
This iPhone did not work with the t-coil on my wife's hearing aids. This subject has been discussed previously in these discussion groups, but suggestions like using TTY or adding bluetooth dongles to the hearing aids are simply not acceptable.
Here are some details ...
My wife wears two Oticon Synchro P hearing aids. They are about 4 years old. They are expensive hearing aids. They have a t-coil setting which she normally uses with telephones, and it works quite well with our Uniden land line phones and our old LG cell phones. The purpose of the t-coil is to inductively couple a telephone or other device to the hearing aid, rather than depending on acoustic coupling which often results in poor sound quality or lots of feedback. With my wife's hearing aids, when turned on, the t-coil does pick up some noise, more like a hum than white noise, but at an acceptable level. When we first tried the iPhone, just placing the iPhone speaker next to the ear with hearing aid with t-coil enabled, caused the noise/hum level to increase noticeably, to a level that was only marginally acceptable. There were other issues, as well.
Except for the noise increase, it did not seem to matter if the t-coil was turned on or off, i.e. there did not seem to be any inductive coupling through the t-coil. Essentially the coupling was acoustic, resulting in poor sound quality.
Last but certainly not least, we also got a loud clicking noise. Once again this was when the iPhone was next to the ear with the hearing aid with t-coil enabled. The noise sounds like a relay clicking, at a rate just slightly faster than I could count. This only occurred in the house, and was gone when we attempted to demonstrate the problem at a Verizon store. I took the iPhone back home determined to find the source of the clicking interference by turning off all the wireless phones and other electronics in the house. When I turned off my Linksys router, an old WRK54G model, the clicks went away. Okay, so I turned the router back on, and turned WIFI off on the iPhone - sure enough, no clicks. And there were no clicks when the t-coil was turned off, or when the iPhone was not in close proximity to the hearing aid (with or without WIFI enabled). So there is a interaction between the WIFI signal, the hearing aid t-coil, and the iPhone in combination.
Next, I tried changing the WIFI wireless channel on the router from channel 1 (2.417 Ghz), to channel 6 (2.442 Ghz), to channel 11 (2.467 Ghz) .. none of this helped, i.e. if WIFI was enabled on the iPhone, and the iPhone was near the hearing aid with t-coil enabled, the clicks were there and very loud.
Next, I looked at some of the router parameters, and noticed that the router sends a short preamble at a default interval of 100 msecs (10 per second) - roughly my guess of the click frequency. Changing this interval to 1000 msec (1 per second) did indeed change the frequency of the clicks to 1 per second!
My theory on this is that we were hearing all the WIFI packets, but most of it sounded like noise, and only the periodic preamble broadcasts were identifiable as clicks. Strange, eh ?
So what now ? Turn off WIFI on the iPhone? No. Change the preamble frequency permanently ? Probably not since I have no clue as to what effect that might have on the various WIFI devices that are used around here. Buy a different router ? Well, maybe, but the iPhone4 only supports 802.11 b/g/n on 2.4Ghz, so it's a toss-up whether or not a newer router would help. Buy new bluetooth hearing aids ? Not anytime soon. Buy the bluetooth add-on gizmo ? Probably not ... Few hearing impaired people really want all that hardware - they just want their t-coils to work.
In the end, we didn't try another unit ... we simply gave up and sent the iPhone back. Since we really like the iPhone, we'll wait until the iPhone5 comes out, try that, and if it doesn't work, we'll find an Android phone from LG or some other manufacturer that does work.
PS
Apple says the iPhone4 CDMA has an M4,T4 (i.e. very good) rating for hearing aid compatibility, "Based on testing conducted by an independent laboratory following the ANSI standard C63.19, "American National Standard for Methods of Measurement of Compatibility between Wireless Communications Devices and Hearing Aids."" I think Apple needs to find a different lab, or do in-house testing of the top 10 hearing aids. A very large group of potential customers would appreciate it.
Windows XP Pro
