atcomsystems.ca/forum Forums TDM Business Telephone Systems NEC Telephones & Systems NEC Mark II RF Interference

I am looking for help with radio interference with some phones in an office I am working with. I have tried everything from replacing all cards in system grounding system replacing station cables, phones and jacks. I have also tried various filters and all filters will not allow the digital signal to go through to the phone either. The signal is somehow being generated from with in the office. I have checked all lines at the RJ and they are all clean. Any help will be appreciated.

99% of the time the rf signal is being picked up via the handset cord.

One test to see if you are having the rf picked up via handset cord is to establish a call, then put call on speaker, if its still there then unplug handset cord from set. If you still have it via just the speaker then you wil have to perform some intricate tasks of applying capacitors within the set.

If the Rf disappears when you put it on speaker than the cord/handset elements may be at fault.
You can put some .001 0r .01 Ufd 50V disc capacitors across the transducers to eleviate the RF.

Also check and see if this is occuring on inside station to station calls or just outside calls.
If its on only outside calls then the Telco cable pairs entereing the building are acting as antennas. Local Telco should provide filters for this.

DJ