View Full Version : Jetstream + Cordless Phones

24-02-2004, 04:20 PM
Since getting Jetstream the quality of sound on my cordless phone has gone down the drain.
I now can hardly hear anyone I'm talking to, and it's a pain as I've had to revert back to my corded phone.

Has anyone had the same sort of issues, or know any sort of resolution?

Heres what I know:

- The phone is a Panasonic KX-TC1045
- I use 3 filters in the house
- I have been told that a splitter may not solve the problem
- Turning the router off does not fix the problem

24-02-2004, 04:29 PM
Some cordless phones have a low frequency transmitter back to the base, or from the base to the phone. These can be badly affected by the Jetstream signal, which is radiated from the phone lines to a small degree, and could easily disrupt the phone signal for the whole house.

Jetstream is carried as a "radio" type signal along the phone line between 1 and 2 MHz in frequency at the upper end. This is probably whats causing your phone problems, and no amount of filtering will help, only physical separation of the phone and the handset from the incoming phone line.

Thats not a practical proposition.
Best solution is to get another phone, but avoid the low frequency ones. Use a DECT system or a 2.4 GHz band phone.

24-02-2004, 04:36 PM
Now thats a new thought that neither Telcom nor Panasonic have told me.
Something well worth considering I bet.

Anything thing I've been thinking about, is that the phone is kind of old, so the battery life isn't the greatest anymore, and it does get quite heavy usage.
Would a new battery help at all? Because I believe that some nights the volume is higher than others.

Graham L
24-02-2004, 04:36 PM
It seems that that phone uses 30-39MHz, so the ADSL frequencies shouldn't affect it. Of course, "shouldn't" doesn't necessarily mean "won't". In fact, the ADSL is digital, so it will have lots of harmonics. :D

If you have a look at what Google gives for "cordless phone problem adsl" you'll see that others have this problem. In fact, it's suggested that Panasonic cordless phones can cause problems to the ADSL link too. ;-)

A 2.4GHz cordless would probably be better. Guess what will happen if you use Bluetooth or WiFi. :_|

24-02-2004, 04:42 PM
So exactly what is the advantage of these 2.4GHz phones?
(sorry, I'm useless at these kind of things)

I assume that something like this:
Uniden 2.4GHz phone (http://www.dse.co.nz/cgi-bin/dse.storefront/403ac41e0103a40c273fc0a87f99067f/Product/View/F7369)

Would that do the trick?

24-02-2004, 04:43 PM
Some of the 38 MHz phones used a 1.75 MHz local link in a duplex method, presumably for separation without the need for sharp filters.

They don't seem to tell you that on the data for the phones. This is what I refer to, and I have heard the problem many times.

And no, a new battery will not help at all if this is the cause.

24-02-2004, 04:45 PM
The frequency listings are here:


24-02-2004, 04:55 PM
Thanks for that guys..

I might just give that Uniden phone I mentioned above a go.

From what I understand, it'll operate at a frequency much higher than Jet stream and cause less interference making my volume increase so that I can actually hear other people on the line.

24-02-2004, 04:57 PM
> So exactly what is the advantage of these 2.4GHz
> phones?

Yes, that would do the trick, however I wouldn't have a Uniden phone myself. You get exactly what you pay for. Thats a cheap price...

These (http://www.dse.co.nz/cgi-bin/dse.storefront/en/product/F9163
) are very good however ... not a cheap price....

As stated, the ADSL Jetstream signal radiates in the 1 - 2 MHz band (and up to several MHZ through harmonics).
The 2.4 GHz phones use a frequency of 2,400 MHz. Its a long way from the interference frequency, which is the whole objective. 900 MHz (0.9 GHz) phones are also a long way away, and work fine as do 1.8 GHz models.

Many 30 - 40 MHz phones work OK, and what works is not a problem. Just dont risk another low frequency one.
DSE is safe, as you can always take it back.

24-02-2004, 04:58 PM
You link came back saying Product Unavailable..

Which product are you referring to?

Graham L
24-02-2004, 05:09 PM
F9163. GF got a destructive
in his link. :D

If you are planning to use WiFi or Bluetooth gear (which both use 2.4GHz) it might be worth investigating the 900MHz or 1.8GHz phones.

24-02-2004, 05:12 PM
I have the same problem, although it's with a corded phone. The phone in one of the bedrooms works fine but the other phone, which is connected to the same jack as my DSL router, is barely usable.

Is this a common problem? Could it be a faulty filter, or something in the configuration of the router?

24-02-2004, 05:13 PM
Sorry about my mass amounts of questions...

But what does this DECT system have over the 2.4GHz???

John H
24-02-2004, 05:28 PM
I have a home network with Jetstart. Part of the network is wireless on 2.4 Ghz (Linksys gear).

I use two Uniden DECT phones between the house and my outside office to provide an intercom and redirect calls, and in the house there are also two Panasonic phones on 900Mhz.

No problems with any of them. There were major problems with my earlier Uniden phones on a different (lower) frequency, but I think that was as a result of major interference from two many similar phones in the neighbourhood on too few channels.

I certainly recommend the Uniden DECT phones (I bought mine from DSE), but probably the other DECT phones recommended to you are of similar quality.

The main advantage of DECT phones for me is the ability to transfer calls and use them as an intercom - you buy one base station with a handset, and then you can buy several other handsets (can't remember the maximum number) so in effect you have as many "extensions" as you like, and can transfer calls like a PABX without the PABX. The handsets sit in a charger cradle - only the base phone is plugged into the telephone jack. Good range, even out of the house and through the tin wall of my office at the back of the section.

John H
24-02-2004, 05:30 PM
I should have added that neither WiFi or Bluetooth have probs with these phones (DECT and 900Mhz), and the phones don't have probs either.

24-02-2004, 05:34 PM
So if i were to buy a single DECT phone to begin with, it'll work just as well as any ordinary phone?

And I assume it should cause an end to my volume problems?

John H
24-02-2004, 05:57 PM
If you buy from DSE they will let you take it back if you aren't satisfied. Worth a try?


Big John
24-02-2004, 06:44 PM
> So exactly what is the advantage of these 2.4GHz
> phones?
> (sorry, I'm useless at these kind of things)
> I assume that something like this:
> Uniden
> 2.4GHz phone (http://www.dse.co.nz/cgi-bin/dse.storefront/403ac
> 1e0103a40c273fc0a87f99067f/Product/View/F7369)
> Would that do the trick?

It wont. I have a 2.4Ghz phone and the interference is bad with just a filter. If I stick a normal phone on the line it is perfect.
I was told if I stuck in the proper splitter then it would be okay as the splitter takes off the phone frequencies onto another seperate line.
I have two lines side by side. One has the Jetstream on it and one is the normal phone line. I have get no interference when plugged into the normal phone line with my cordless.

24-02-2004, 07:06 PM
So your saying that I need a splitter?

The guy at Telecom said that it possibly wont fix my problem.

I have no way of being sure if it will fix my problem if I went ahead with it.

24-02-2004, 07:07 PM
Watch the quality of your filters. Commonly available ones may be less effective I was told.
I used Nokia filters with no problems, the shop I dealt with kept them out the back to supply in preference to the "house brand" on the shelf.

The level of ADSL varies depending where you are relative to the exchange. This will also have an effect, if the signal level is high. Some could "break through" the filter I presume.

A full install with splitter may improve things but the actual location of the wiring and where they need to fit the splitter would determine that. The cost would go a long way to a better phone.

I have 2.4 GHz Panasonic cordless as well as 2 DECT phones that are fine with my Jetstream.
The 2.4 GHz has slightly longer range but the DECT are better for reasons already given. Basically the DECT are like cellphones to use, with loads of features.

I had to give up on a Uniden 30 MHz cordless.

24-02-2004, 09:02 PM
According to other reports being recorded on forums around the net you indeed have a problem being experienced by others.

Go here (http://unixathome.org/adsl/archives/2004_02/0058.html) to learn more ...

Big John
24-02-2004, 09:21 PM
> The level of ADSL varies depending where you are
> relative to the exchange. This will also have an
> effect, if the signal level is high. Some could
> "break through" the filter I presume.

Well I do live only 2 blocks away from the exchange so that may be my problem. However as I said I get round it by using a standard phone on the Jetstream line and a cordless on the other line.