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Internet connection goes down evereytime someone calls the fax machine

dolsson asked

Like to title says: Everytime someone call our fax machine the internet goes down.

I don't know if this problem started to occur when we upgraded the internet to 24/2 or when we implented our new firewall ( cisco asa 5505).

However, we have replaced the splitter (who split the analog from digital signal) two times, and replaced the modem two times (the modem comed from our ISP).

We have two different numbers. One for our telephone (IP telephone) and one analog to our fax machine.

I've called our ISP and told this problem like 6 times, but it seems like they can't solve it. I don't know if the problem is on their side, or on us.

Anyone have any idea what the problem might be?

Watch Question

What is the actual problem here .. You get a call to your Fax number the Internet Goes down.?

Is it the same fax number in which you have your internet activated through Modem ?

And where have you placed your ASA firewall ?


Yes it's the problem. When we recieve a fax or call the fax number, our internet connection goes down.

Yes. it's the same number that our modem is connected to. But we have another number to call our telephones.

First we have a splitter from the modem to the tele jack. Then, the fax cabel is connected on the splitter.

From the modem is a patch cabel to ASA firewall, and from ASA firewall to the switch and server etc.

Then i don't think its your Firewall end issue.

Its the problem with your Telephone Line. Check for Some BT equipment Installed at the Telephone exchange .

May be a wiring problem from your BT poll to your house or from exchange
The fault is commonly known as the pairs in the cable are legged.

Each single pair is coiled to hold the magnetic field.

If the cable is legged this means when the cable was first installed it is paired with wrong white pairs .

Legged cables works fine for voice call but both internet and voice wont work properly .. Request your ISP to check the Cabling to your FAX machine from the BT box. Or rewiring will work for sure .

Try this: disconnect the fax machine and connect a telephone, then call your fax number and answer it.

Does the internet drops with that test?
Les MooreSr. Systems Engineer
Top Expert 2008

Do you have a DSL filter on your fax machine?
Don't know the reason, but after trying 6 different fax machine, one Samsung fax actually did work.
So I don't know why the problem accured.

Thank you all anyway


Don't know the reason why is suddenly worked