Intercom system

[John120/240]

I have an intercom system with squak boxes, kitchen, 2 bedrooms, & basement. M / S Sound brand. There is static on the system at each location.

Standard doorbell button at front door, that sounds a chime thats heard on each squak box clear as a bell.

They do not use push to talk feature between rooms. How can I eliminate
static. Thank You John

 

[MAK]

What kind of cable was used between devices?

 

[TwinCitySparky]

If you find you do have the proper cable then start process of elimination.

 

[MAK]

I have more often than not found that intercom cabling was shielded. Some of the systems I have worked on that did not use shielded cable always had some noise on the line but I would not describe it as static.
I have you thoroughly checked your terminations? Perhaps a loose termination making intermittent contact could cause your problem.

 

[MAK]

If the cable is shielded you can try grounding it at one end to see if it will clear up. This maybe trial and error.

 

[IllinoisElectrician]

If the cable is shielded, ground it at both sides, m/s brand provides a lug on their control panel. Other than than, the doorbell speaker positive usually goes to a seperate lug, as well as patio wires. With newer m/s units, you cannot connect more than 1 doorbell to any note in the chime module.

Also if using a 4 wire system, make sure that you have changed the jumper setting! This can make some serious noise.

Hope some of this helps, I hate noise problems at the speaker level! (Preamp can usually be fixed easily .

 

[TwinCitySparky]

If the cable is shielded, ground it at both sides,

This is directly contrary to what I have been taught. With a shielded low voltage signal cable you only want to ground one end to avoid the dreaded ground loop.

 

[John120/240]

Thank You all, very helpful.

 

[dbuckley]

This is directly contrary to what I have been taught. With a shielded low voltage signal cable you only want to ground one end to avoid the dreaded ground loop.

Correct.

Unless what you are going to connect it to at the other end is isolated from ground, in which case connection good.

 

[MAK]

What is the "MS Brand"? I googled it but I not sure if I am looking at the right site. Anybody got a link?

 

[TwinCitySparky]

Its a pretty common intercom system owned by a division of Linear.


http://www.linearcorp.com/intercom_music_speakers.php

 

[TwinCitySparky]

Correct.

Unless what you are going to connect it to at the other end is isolated from ground, in which case connection good.

I guess I am thinking of the audio world where you never terminate the shield of a balanced audio line at both ends or the "oeo rule"

 

[MAK]

Its a pretty common intercom system owned by a division of Linear.


http://www.linearcorp.com/intercom_music_speakers.php

Thanks for the link and info!
I did not know linear was making intercoms. I really only use their wireless transmitters every now and then.