FM Systems

I am new to FM and do not know how things work, our audiologist is not helpful (we are going to a new one in a couple of weeks), the school is not going to offer, I need to specifically tell the school My son needs XYZ…

Little guy just started Kindergarten, the classroom is set up with a sound system.

the teacher wears a mic and it is attached to a CSi Model VXM 168LTS transmitter.

there is a receiver in the room, a CSi Wireless Mic Receiver Diversity MWD-100L

There is an amplifier I forgot to write down what the model/brand is

The sound is fed into the schools PA system speakers

My son wears Phonak eXtra 211 AZ BTE’s bilaterally

I would like to know is it possible to get a receiver for son to wear that grabs the signal/sound from the teachers transmitter and directs it into his hearing aids.
… how is this going to work with his aids, is having her voice over the speakers in the room and direct to his HA’s be too much?
I have looked on Phonak’s website and see the type of boot, receiver and transmitter he would need if they were all Phonak brand, but because the transmitter the school uses is another brand I do not know how that would work. Can someone help me out figure out what type of equipment he would need?

I have looked for CSi brand… I’m getting goggle matches of CSi company focusing their efforts on GPS technology and I am also finding CSi SPECO as a company/brand, well SPECO and they have CSi in front of some of their items.

Any help??

Have you tried the Conversor Pro? a very simple but effective FM System which can be used by all ages. For more information please visit

when it word FM comes to mind, I think about Phonak. - I would check them out.

An alternative is the Oticon Amigo…

Once in a while we get someone on this forum that adds nothing to the forum but to run an add for their product. Conversor seems to be one of those people.

agree they should be ban

My daughter had a similar experience during her college education.

She already had Phonak BTE hearing aids, and added the integral FM receiver for her hearing aids. She then used her (at the time Handymic) to receiver the teachers voice by 1) having the teacher wear the Handymic or 2) plugged the output of the schools system from the “monitor” jack as an input into the Handymic.

Using the Phonak system to transmit and receive the teachers voice keeps things simple as to getting the school’s frequency compatibility issue out of the way.

There is no doubt the FM got her thru college and beyond. BTW, she’s now a Pediatric ENT surgeon.

I tried to look these up and they just don’t seem to be referenced online
which is really pretty odd… CSi must not be close enough or its a really old unit.
CSi Model VXM 168LTS transmitter
CSi Wireless Mic Receiver Diversity MWD-100L
Phonak, oticon Amigo comply with
FCC FM frequency range 216-217 MHz. There is the 72-76 MHz range that is not used as much any more. It seems you at least need an ear level receiver. They want absurd amounts of money for them. Here are a couple of informative links.
Below is a link to the receiver you probably need for the Extra bte. There are 2 ways to look at this, the design integrated one (ML9i) is one piece , more secure on the aid and smaller than the AS9 shoe with an independent mlxs receiver. Breaking them would have been the issue with any of my kids. 5 years old they would have had to have tasted at least once.
Down side is the design integrated fit only on the aids listed.
verify the kindergarten frequency range!!

Technically, you don’t need to interface with the system in place. You can use the Phonak transmitter (the teacher can wear both transmitters) and the receivers will boot to the hearing aid. You would bypass the existing system altogether. This gives you the flexibility for the next classroom that doesn’t have the same system.

I researched using just the model numbers and found technical specs on the transmitter and microphone, but you didn’t have the model for the amplifier. The system that is in place does not operate on a frequency that a standard FM system can pick up. But the amplifier should have an audio output jack. It may already be used to send the sound to the PA speakers. If it does have an available audio output jack, you could plug an FM transmitter into it with an auxilary input cable. Then what goes through the amplifier would also go through the FM transmitter. (Again, the teacher can simply wear the transmitter and you can bypass that system altogether).

So when you find an audiologist to work with you on the FM system components best suited for your son, you can use the system independently, or try to use the auxiliary cable with the classroom amplifier’s audio output jack.

In my opinion, you probably don’t want to base any FM choice on interfacing with existing equipment (this year, in this classroom). If you can, it’s a bonus for the teacher who won’t need to wear the 2nd transmitter. But many teachers have worn two.

Almost all FM systems (receiver and microphone) (Phonak, Sennheiser, Oticon) can interface with an external sound system using THEIR SYSTEM’S MICROPHONE as the transmitter. This is a plus as you are not locked into any one system that may change with classroom and / or school grade.