DSL line: surge suppression OK or not?

By robo_dev ·
My DSL service has gotten a little flaky in the past month, so I've got a visit from the phone company service tech set for tomorrow.

When checking the connections, I realized that my DSL line goes thru the telephone surge suppressor of my APC UPS (and it's been plugged into that for about a month (dowt!) ).

APC claims less than 1dB loss thru their unit, and I'm going to do some testing to verify that.

DSL surge suppression: Good idea or not?

How much signal loss should DSL be able to sustain before it gets flaky and starts to have trouble connecting?

What I've seen are connection failures when doing the PPP negotiation, such that the DSL modem re-cycles the connection (drops sync and tries again, and again, until it works). I've got DSL filters where they are supposed to be, and the wiring is all in good shape.

This conversation is currently closed to new comments.

Thread display: Collapse - | Expand +

All Answers

Collapse -

Determining factors

by mjd420nova In reply to DSL line: surge suppressi ...

So many things can affect the wiring of your phone lines and it may be that you are it the limit of attenuation with the surge suppresor in place. In most cases, all that is needed is to have the phone guy re-punch your line on the pole and again in the in-house termination panel. Sometimes you might have to re-terminate the line again in the wall outlet you're using for the DSL modem. This would be your responiblity as the phone company resonibility ends at the in-house panel. If you have them do anything in-house, it could cost you some money but it depends upon your specific agreement terms on your phone bill. Normally adding two more jacks and the suppressor connectors would not be enough to reduce the signal below the minimum threshold needed for adequate performance.

Collapse -

Filters and Loss

by TheChas In reply to DSL line: surge suppressi ...

I did not look at the APC specifications. However, if the jacks are rated as phone jacks, that 1 DB of line loss would be measured at voice frequencies and not the higher DSL frequencies. Therefore, it is possible that your DSL problem is caused by the surge protection and line filters in the APC unit.

I do have a surge suppressor on my DSL line. Mine is in the form of a POTS splitter. One of the many advantages of using a POTS splitter is that your home phone wiring is isolated from your DSL wiring. You don't need the line filters at each device. And, you would almost need a full failure of a device or cable to impact your DSL signal.

I installed my POTS splitter right next to the box where the phone line comes into my house and then connect the phone lines to the phone output of the splitter.


Collapse -

My first port of call would be your ISP.....

by Peconet Tietokoneet In reply to DSL line: surge suppressi ...

Call your ISP and see if they are having any down time with switching over servers etc.
I have had this sort of trouble and found that my ISP did have trouble with their spare servers.
Detach the dsl cable from the surge plug and connect it directly to your router/modem to see if that brings any joy.

Hope all works out.

Collapse -

The results, key was my satellite box causing problems.

by robo_dev In reply to My first port of call wou ...

First of all, AT&T rocks. They show up at 8:01AM for an 8-12AM appointment, and the tech knew it all, was very helpful, and fixed the problem.

We determined that signal levels were good, with or without the surge suppressor (which was found to drop signal levels by less than 1db).

There were two issues that were noted:

First, the number of CRC errors on the downstream side was excessive and second, the number of 'errored seconds' was a little high, possibly indicating that something was knocking the DSL circuit offline.

We determined that the CRC errors were coming from the in-house wiring. We unplugged all phone devices in the house, and the CRC errors continued, but then the tech asked me if I had a satellite receiver with a phone connection...he says people tend to forget about these, and the sat installers tend not to put DSL filters on the line.

What can happen, also (he said) is that the sat receiver may knock the DSL circuit off-line when phoning home.

Sure enough, I had no DSL filter on the phone hookup for the sat box. He put on a filter and the CRC errors stopped.

I have an alarm panel that has no DSL filter, but the tech said that he rarely has ever needed to put a DSL filter on the alarm panel. (it takes a special Rj31X filter, anyway).

So far the connection is rock solid, only a couple of CRC errors, and the throughput tests indicate I'm getting every bit of bandwidth I'm paying for.

So the bottom line: surge suppressors don't hurt anything, AT&T does a good job, and make sure your satellite receiver phone connection has a DSL filter.

Collapse -

Thanks for the Feedback

by TheChas In reply to The results, key learning ...

It is always good to get feedback and know what corrected the problem.

It was very good to hear that the APC surge protection did not affect the DSL signal.

Your results make me even more secure in my belief that installing a POTS splitter right where the phone line enters the building is the way to go for DSL.

With the POTS splitter you both cannot forget to install a filter on a device, nor can a device easily cause the DSL signal to disconnect.


Related Discussions

Related Forums