Telephone Double adapters

Does anyone know if the BT ASDL MF50 filter item code 008072 that meets SIN 346 (Aug 2004) has been designed so that it will not operate with a telephone double adaptor attached? To assist further the identification of the product, the filter design tapers towards the line connecter end and has slightly concave sides.

The reason I ask is that this filter has been sent to me to replace my existing filter as part of the attempt by my ISP to increase my line speed towards its capacity of 3mbps. However, nothing will connect through the filter (broadband or telephone) if I try attaching a double telephone adaptor.

My existing filter BT ADSL MF50 item code 011249, rectangular shape 2" x 1.5" has run 2 telephones and my broadband connection without problems (as far as I know) for 2 years. My ISP is also suggesting that I should change my filter every 3 months. Is this necessary?

Incidently, my attempted speed upgrade is proving troublesome having ranged from 0.1 to 1.3mbps during the 10 day upgrade settling in period. It appears to have settled at the speed that I was previously getting of around 0.45mbps before the exchange was upgraded last year to handle 3mbps from 0.5mbps.

"My ISP is also suggesting that I should change my filter every 3 months. Is this necessary? "

That is a new one and suggests it may be worth ignoring any other advice.

NOTE: The exchange can handle the full 8Mbps, just that because you have a long telephone line you are getting less.

Are you saying the telephone double adaptor does not fit into the phone socket on the MF50? Or that you cannot plug the MF50 into the adaptor and have an extension running off of the doubler too?

If the latter that is not the best way of doing things, as extensions can bring down your broadband speeds

"My ISP is also suggesting that I should change my filter every 3 months. Is this necessary? "

Judging by the apparent high failure rate of BT MF50 filters perhaps the ISP was referring to the average failure time they find. :-)

Edited by deleted (Mon 07-Jul-08 14:57:23)

A doubler does just that - it's just a plug with two sockets moulded on the back and nothing would be "designed not to work" with a doubler. If it isn't working then it's almost certainly either just a physical problem (the bits won't fit together properly) or there is an electrical problem with one or other of the bits.

As Mr Saffron has said using doublers before the filter is bad news. Using the doubler on the phone o/p of the filter will be fine (assuming it fits) as that side of the filter has no ADSL signal so you can't mess it up.

I've a couple in my travelling kit and they seem to survive

Did I hear a little meaow?

This cropped up before recently.

Filters don't "wear out" but they can fail. A decent quality one should last for years.

Perhaps it is just because they are very common but the one I always seem to come across that fails is the MF50.

It's a bit like that fatal water stuff then - apparently a very high % of people who die have drunk some in the preceeding week. I'm sticking to booze - much safer.

Thanks folks for your help to date.

For clarification to you all I confirm that I believe I am using the double telephone adaptor correctly I connected the new filter in the same way as the 'old' filter that has worked happily for 2 years so far as follows: 1) - The filter is plugged into the main or first telephone point on the inside of the house 2) - The broadband cable runs from my computer to the DSL socket on the filter 3) - Into the phone socket on the filter I slip the telephone double adaptor (I have tried both my existing adaptor and purchased a new one in case there was some compatibility problem with the new filter) 4) - Then I plug one phone directly into each socket in the double adapter to give me my two phones working off the filter.

With my old MF50 everything still connects but with the new MF50 connected in this way I get no dialling tone on either phone and broadband fails to connect - I get a message to say that I have a line problem. However, if I remove the double adaptor and plug either phone in turn into the new MF50 I have a dialing tone on either phone and broadband connects as well.

I am therefore, at present sticking with my 'old' filter even if it is true that it may compromise my connectivity speed but I would like to understand if at all possible from the Thinkbroadband collective experience, what the problem might be.

Even with this filter issue, I believe there is potential to speed up my connection (my ISP is still researching this for me - they have admitted to me today to 'internal technical problems'). This filter issue though seems intriguing.

Well you can test whether the new filter makes a difference easily - look at the connection information in the ADSL modem.

As for the doubler sounds more like a physical issue, or your telephones are pulling down the line which was just about OK with the old filter, but new one is marginally different.

Other than the daft 3 month advice from the ISP, what makes you think it may be the filter

With the way you are connecting it I can just about understand why there may be a ring problem - you have two phones trying to operate off the ring capactitor in the filter which is just possibly not good enough to support that (exactly the same problem as too many phones in the BT master exceeding the REN). I suppose in that regard it may well not be designed to operate with a doubler.

What I can't fathom out is why the ADSL won't connect though. You should be able to do anything on the phone side without it impacting the adsl - right up to shorting it out.

It seems to me that your new filter is suspect as to my mind it should be capable of doing what you are asking of it.

"Other than the daft 3 month advice from the ISP, what makes you think it may be the filter"

I have only, in the last few days, learned that when 'upgrading' broadband speeds, 'consistency testing' takes place for the first 10 working days so that the ISP may discover what 'sustainable' higher speed is available on a line. I was not made aware of this necessity by my ISP at the time of entering into a new upgraded service contract.

Following contract activation my modem, BT Voyager 105, began showing a connection speed ranging between 2.1mbps and 3.7mbps but I felt this was not happening in reality. I then went to the Thinkbroadband' excellent speed testing facility. This evidenced an approximate halving of my connection speed from around 0.45mbps to around 0.2mbps, rather than getting close to the 6x increase that I had been advised was now available to me as a maximum for my line. BT's broadband test facility would not even run on my line after 'activation date'.

I contacted BT who told me they detected a 'problem' with my broadband connection and suggested I contact my ISP. This is when the filter issue arose. I felt the filter advice was daft and thought no more about it until the filter arrived (I had originally suggested not to send one!) Following my instincts and frustrated that connection speeds had reduced, I tried a different route to ISP contact. This time I was told that due to 'internal technical problems' (I now read this to mean staff and/or process failures) my account upgrade had not been activated properly. I was given a new activation date. This date passed at the end of last week. Yesterday, on contacting my ISP again, I was told that the 'internal technical problems' should be overcome in 48 hours. Something is now happening as my Thinkbroadband speed test today has shown a connection speed of more than 3x my normal average of 0.45mbps but only after a double hiccup at sign on. At the first attempt there was no broadband signal getting through. The system advised restarting the computer. At this second sign on, my broadband connection was so slow as to be unworkable. On signing on again but without restarting the computer, I obtained this 'lightning' speed - compared to what I have been used to. All of this with the old MF50 in place and both telephones working.

My initial thoughts on the new filter were that it was faulty as, on receipt, I immediately replaced the old filter after first signing off from broadband on the computer but nothing worked, as explained in my previous posts. So I commenced the laborious process of experimenting with the different connection combinations to see and confirm which combinations worked and those that didn't. This lead me to post my observations for advice on my finding. My forum post question is the only combination that doesn't work. I wondered if I had missed something - a technological 'improvement' or a fault as I initially suspected. The former now felt more logical than the latter given my experiment findings. However, before exploring ways of changing the telephone placements in my house, I thought I would seek wider confirmatory advice with a forum post on whether or not filter/doubler combinations are now effectively outlawed, as my ISP suggested, to achieve greater broadband speeds.

Apologies for the long explanation but you did ask!

Thanks "Going Digital" for the connection to your site. I hadn't looked beyond the filters supplied by my ISP. The fact three phones can be used through your XF-1e professional and exceeds the BT SIN #346 gives me some comfort about being bullied into using one phone only through a filter.

Thanks for your analysis, "Kwikbreaks". I will take this up with my ISP. I note from "going digital" that their filter supports up to three phones so at least it eliminates my concern that faster connection speeds are dependent on no more than one phone running off the filter.

In reply to:

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being bullied into using one phone only through a filter.

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faceplate filters, as used by BT, put all the phones through a single filter.

The filter's job is to prevent the dsl signal getting into the phones where it may cause problems and to prevent the loading of the phones attenuating the dsl signal. You can put whatever you like on the phone side of the filter and it should have no impact on the dsl. Failing to ring is a different matter.

Have you tried a single phone into the doubler? It would show whether the problem is caused by trying to run two phones off the filter or if it is a continuity type problem with the doubler.

Thanks for the tip and info. As Kwikbreaks suggests 'knowledge is power'.

Have you tried a single phone into the doubler? It would show whether the problem is caused by trying to run two phones off the filter or if it is a continuity type problem with the doubler.
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Thanks for the suggestion. I have tried again.

This time broadband worked with whatever combination of phone I tried where the phone is plugged directly into the filter phone socket. It worked also with the doubler in place as well whether phones were connected or not. I cannot think why broadband connectivity did not work when I first tried it. It did fail to connect on the three separate occassions that I tried.

However, with broadband now working the phones either singularly or doubly connected will not work through the doubler.

When I then revert to the original filter all connectivity combinations work. My broadband speed has not settled since the upgrade so the speed test has not been able to prove yet that the old filter is interfering with my speed upgrade.