RadioShack Intercoms...

[kg6nlw]

Maybe someone can help me with this. I have RadioShack 43-124 intercoms throughout my house.

I recently just picked up a pair of RadioShack 43-3102 intercoms. When I set the same sub-tones, the two do not interact. I know the 43-124's are newer, but what would be the reasoning as to why the newer won't hear the older? I have tried, I think, all the possible sub-tones on the older intercoms to try and link with the newer system.

Any ideas or thoughts?

Regards,

-Frank C.

 

[N2AL]

Maybe someone can help me with this. I have RadioShack 43-124 intercoms throughout my house.



I recently just picked up a pair of RadioShack 43-3102 intercoms. When I set the same sub-tones, the two do not interact. I know the 43-124's are newer, but what would be the reasoning as to why the newer won't hear the older? I have tried, I think, all the possible sub-tones on the older intercoms to try and link with the newer system.



Any ideas or thoughts?



Regards,



-Frank C.

Are they wired or wireless? If wireless it’s possible they use two different frequencies.

 

[kg6nlw]

They are called Wireless intercoms, but they're both in the 900Mhz spectrum but...

Regards,

-Frank C.

 

[iMONITOR]

Maybe someone can help me with this. I have RadioShack 43-124 intercoms throughout my house.

I recently just picked up a pair of RadioShack 43-3102 intercoms. When I set the same sub-tones, the two do not interact. I know the 43-124's are newer, but what would be the reasoning as to why the newer won't hear the older? I have tried, I think, all the possible sub-tones on the older intercoms to try and link with the newer system.

Any ideas or thoughts?

Regards,

-Frank C.

I have a few of the 43-3102's. Did you match the DIP switch settings n the battery compartment?

 

[kg6nlw]

I have a few of the 43-3102's. Did you match the DIP switch settings n the battery compartment?

Yes I did. I matched them to what I already had on the 43-124 models.

Regards,

-Frank C.

 

[iMONITOR]

If you have a scanner, you could try using the close-call feature, or spectrum analyzer to determine what frequency each model is using.

 

[kg6nlw]

If you have a scanner, you could try using the close-call feature, or spectrum analyzer to determine what frequency each model is using.

It looks like the older intercom is on 911Mhz and the newer ones MIGHT BE on 910Mhz but I didn't get a full scale hit like I did with the older, so that solves that...

Regards,

-Frank C.

 

[iMONITOR]

They have to do something to provide some isolation/privacy between them, so you and your neighbors don't hear each other.

You could always sell the ones that don't match, and buy some that do.

 

[kg6nlw]

They have to do something to provide some isolation/privacy between them, so you and your neighbors don't hear each other.

You could always sell the ones that don't match, and buy some that do.

I just got these "new to me" ones off eBay. You'd think with how scarce they are, isolation wouldn't be an issue, especially with the amount of possible sub-tones. Think FRS/GMRS but with about half the amount of PL tones.

Oh well...Back to eBay I go...

Regards,

-Frank C.

 

[RFI-EMI-GUY]

You would need a spectrum analyzer, scanner or frequency counter to figure out the exact channels. The User manuals are not helpful. According to the FCC certification tests for both they operate on like four discrete channels between 910 and 913 MHz:

"Product Description

The Equipment Under Test (EUT) is a Wireless Intercom (Transmitter Portion)
operating at 910MHz, 911MHz, 912MHz and 913MHz. The EUT is powered
by 6.0VDC (4 x “AA” size rechargeable batteries or AC/DC adaptor 120VAC
60Hz input, DC 9V 350mA output). After switching on the EUT and press the
talk button. User can talk to each other with same channel selection. The
number of channel can be selected is four and the channel switch is located in
battery compartment. Also, it has LOCK function – use the intercom as a
room monitor, CALL – use to calling another station, AUX input – to transmit
audio to each intercom and Weather radio alert enabled function – listen to the
radio or receive weather alerts in any room with an intercom"

However, it appears from the FCC certification test report that one model might operate about 35KHz higher than the other. So if that is the case, you are hosed.

I would try every combination of channel 00, 01, 10, 11 to see if you get a busy light on a receiving unit, and then every combination of subtone 000,001,010,011,100,101,110,111. until it unmutes. You might get something, but it might be right off channel. Read the instruction, you might need to power up reset to set channel.

 

[kg6nlw]

Strange that there is no channel selection, just a sub-tone selection...

Regards,

-Frank C.

 

[RFI-EMI-GUY]

Strange that there is no channel selection, just a sub-tone selection...

Regards,

-Frank C.

How so?

Sent from my SM-T350 using Tapatalk

 

[spongella]

What does the manual say? One other source of information would be the FCC wireless device database. First, get the FCC ID number for the intercom, it should be somewhere on the unit, either stamped into the body, or on a tag somewhere. Then go to: https://fccid.io/

Put in the FCC ID# and see what information the manufacturer has submitted to the FCC.

Hope that helps.

 

[kg6nlw]

How so?

Sent from my SM-T350 using Tapatalk

Your quote from the EUT says "User can talk to each other with same channel selection. The
number of channel can be selected is four and the channel switch is located in
battery compartment." But that's just the sub-tone selector switch, in which case there are 5 dipswitches...Oh well, I'm just hosed on this pair then.

Regards,

-Frank C.

 

[RFI-EMI-GUY]

Your quote from the EUT says "User can talk to each other with same channel selection. The
number of channel can be selected is four and the channel switch is located in
battery compartment." But that's just the sub-tone selector switch, in which case there are 5 dipswitches...Oh well, I'm just hosed on this pair then.

Regards,

-Frank C.

The switches are binary. Two switches get you 4 channels and three get you 8 subtones.



Sent from my SM-T350 using Tapatalk

 

[kg6nlw]

The switches are binary. Two switches get you 4 channels and three get you 8 subtones.



Sent from my SM-T350 using Tapatalk

So...On a slightly different note related to these intercoms. I just used my SDR setup and both sets transmit on 910Mhz...So something isn't right.

Regards,

-Frank C.

 

[RFI-EMI-GUY]

So...On a slightly different note related to these intercoms. I just used my SDR setup and both sets transmit on 910Mhz...So something isn't right.

Regards,

-Frank C.

Are they both transmitting exactly on 910 MHz? The channel bandwidth is only about 40 KHz so they need to be very close within a couple KHz. If you are satisfied they are, then toggle through all of the subtones. You might have to power up and down to get the tones set.

Sent from my SM-T350 using Tapatalk

 

[kg6nlw]

It looks like it...I'll have to toggle things tomorrow to see what happens!

Regards,

-Frank C.

 

[N2AL]

Hi Andrew,
I tried to post a comment to the thread but it won't let me for some reason.
I only have the 43-3102 intercoms but they work great, except for one that died (it sounded like it was off frequency but I saw no easy adjustments inside).

For the 43-3102:

CH# on cover DIP switches Freq
1 1 1 914.0
2 1 0 912.0
3 0 1 911.0
4 0 0 913.0

My Pro-528 scanner's search feature found these. But the scanner isn't sufficiently wide band FM for the intercoms to sound very good.
Intercom to intercom they are really HiFi sounding.

Feel free to post this if you think it helps.
Cheers and 73,
Dave, N6KL

Frank sent me this email after he was unable to post to this forum. I have posted the message for everyone to review, and to see if we can further give him a hand.

 

[kg6nlw]

Frank sent me this email after he was unable to post to this forum. I have posted the message for everyone to review, and to see if we can further give him a hand.

I didn't send that but thanks for the info!

EDIT: I did some testing with my SDR Dongle and the older 43-3102 DOES NOT want to change channels despite dip switch change and power cycling. It stays on 911MHz. The newer 43-124 intercoms are set to 911Mhz.

Regards,

-Frank C.