Normally I post about my HCI research but I thought today that I’d do something which is unrelated but may be of use to some people. Earlier this year our house’s landline was being bombarded by nuisance calls. We had, on average, six calls a day from sales persons, phishers and fraudsters. I managed to find a cost effective method of stopping them using safe lists.

The Problem:

There’s been a rise in nuisance calls in the UK recently.  Despite action finally being taken over some of those responsible it may be a long time before these calls are totally stopped by the authorities. Therefore, if you want an end to nuisance calls in your home you’d be required to stop them yourself.  There are already some methods for stopping them, such as going ex-directory or joining up to the TPS.   However, these alternatives won’t work completely.   Devices such as Trucall or phones like the BT6500 can do a much better job but cost money.  I was lucky in finding a way of stopping these calls with our existing phone set up.

The Solution for Landline phones:

The method I used was to essentially create a safe list for the phone.  Anyone on the list, such as friends and family ring through as normal.  For everyone else the phone rings silently before putting them through to the answer phone.

What you need:

• Caller ID on your line
• A phone with night-mode
• An answering machine (optional)

The setup:

• Ensure night-mode is enabled and set to be on 24 hours a day, everyday.
• Input the numbers of all the people you want able to ring you as normal into your phone and ensure they are exempt from the night-mode rules.
• Ensure the answer phone is on. (optional)
• That’s it – though there may be draw backs as mentioned under results.

You can do without the answer phone if you’re entirely confident that you’ve safe listed everyone who will legitimately want to get in contact with you.

Our phone is a Panasonic KX-TG8321 which we got for relatively cheap.  This model is pretty good since it has the answer phone built in, though Panasonic have bought out a range of similar models recently which may be better.  Luckily our phone’s answering machine is smart enough to disregard silent calls.  If your answering machine doesn’t do this you may end up getting a lot of blank messages due to the large number of silent calls out there these days.

The Solution for mobile:

Despite not having any huge problems with nuisance calls on my mobile phone I decided to take precautions anyway.  I have an android phone, for which there are a wide variety of apps that are specifically made to appropriately manage unwanted callers.  I have a feeling the same would be true for other smart phone operating systems.

I opted for the avast app since it also throws in a lot of other features in addition to the call filters.  Under SMS and Call Filters I simply made a grouping for hidden and unknown numbers and set any calls and texts from the group to be blocked.   This will send all callers outside your android contacts straight to voice-mail.  In addition to this, any texts from unknown senders get deleted without bothering you (you can get the app to log blocked texts in case you’re worried about missing one).

Results:

We have had no nuisance calls get through since setting up the phones in this way.

One side-effect though is that calls coming from people whose numbers that haven’t been put into the phone will not ring.  However, if a call is important, i.e. not sales, the person calling should leave a message, then you can call them back and/or add their number to your safe list.

Some of our friends have been put through to the answer machine silently because they withhold their number.  Despite their number being in the phone and having caller ID, the phone cannot identify whose calling if they withhold their number.  The solution to this in the UK is to ask those who call you to put 1470 before your number when dialling   This will keep their number hidden from others but will show your phone their number so it can let them through.  This essentially makes your number four numbers longer but with electronic phonebooks this shouldn’t be a major problem.

Conclusion:

Of course you may not think nuisance calls are that bad.  The number of unwanted calls a line gets seem to vary.  Ultimately, the decision on whether to set up a system like this comes down to whether you’d prefer to answer the occasional nuisance caller or have the occasional legitimate call sent to answer phone.

If you’re interested in possible ways that unwanted correspondences could be managed in the future my article on advanced safe lists may be of interest to you.