Anyone recognise this intercom equipment?

In article , Roger Mills scribeth thus

Theres a firm in London SRS doorentry it might be one of theirs if not they may well know who made it..

for each flat, thus:

door, thus:

flat - ok.

speaks, I can hear them - but they're not likely to

hear my instruction to push the door!

wondered whether any of you might recognise it. I'd

It's been many years since I dirtied my hands on that stuff, It was when my Grandmother was alive and I wired an extension to her chair-side table using an old POTS phone with most of the guts removed.

IIRC the system is very simple; primitive in fact. A DC PSU, carbon microphones in the outside panel and the handsets No amplification! The phone cradle is badly made, hook switch leaf spring need adjusting contacts cleaning, etc. It's very basic stuff, just make a sketch of how the cable connects to the cradle first.

At the time I was maintaining a lot of Panasonic GX PBAX systems, so had a supply of replacement carbon mic inserts.

New handsets for sale here

Try removing the handset base from the wall and Google any part numbers you find on the rear. I install

You could wire a lamp and a buzzer so it works with people that are deaf. There should be enough juice across the solenoid to do it. Is it against the DDA to have holiday flats with an intercom that deaf people can't use?

Sometimes the carbon granules are stuck together and banging the handset on something hard loosens them up. Worth a try if you are going to replace it anyway.

Thanks for the links. I've emailed them with the pics, and am awaiting a reply!

Grandmother was alive and I wired an extension to her

That sounds like the one! When I took the front panel off the wall-mounted bit, I couldn't make out how the cradle switch was supposed to work - it seem to have a couple of vertical bits of coiled springy stuff - a bit like curtain wire from memory - but I couldn't work out what they did!

supply of replacement carbon mic inserts.

I've got a few old phone handsets lying about - am I likely to be able to cannibalise one of them successfully?

Those look hopeful - thanks for the link.

That's the cheapest option so far - I'll try that!

Useful advice - thanks!

I can't see how that would help *speech* to be heard from a duff handset.

I've no idea - my family are not deaf, and we are the only people who use the flat - it isn't let out to Jo Public!

The two coil springy bits are the moving contacts of switches to connect the mic and speaker.

The square wire 'hoop' over them is the common wire, IIRC. It is liable to working loose or dry joints where it attaches to the PCB. I think the newer handsets have a 'proper' switch.

Probably physically too big to fit, but might be worth a try.

Used to have a whole box of those handsets ripped out of the last flats I lived in.

Owain

I've seen quite a few of these, none I've worked n have or had carbon mic's usually electret or moving coil ones!...

This is the landlord or management companies responsibility.

Yes, on thinking about it a bit moire, I concluded that the problem could well be with these switches rather than with the mic, so I decided to replace the whole handset.

On consulting two of the companies suggested by people responding to this thread, the handset has been identified as a BSTL-801. One of the companies has an Ebay presence, and is supplying a handset for £15 inc. postage - an amount which I'm happy to risk.

Yes indeed. However, the management company is owned by the tenants - and I'm one of its directors. I *could* get a commercial outfit to look at it, and the company would reimburse me - but I have a vested interest in doing it as economically as possible - and am happy to invest a few bob in replacing the handset in the hope that that fixes it.

Hi You have a Bell Systems door entry system,with bell 801 handsets.the front panel is a standard surface unit. Very easy to maintain parts are cheep and readily available phones use a 5 wire system all conected (usually) at the front door call unit which contains the speech amp and call buttons,A 12v ac transformer is usually mounted remotely to power the system. The handsets should "warble" when called and this should be heard at the fromt door. If you need any further info repost or check Bell Systems web site. HTH CJ

The modern ones warble and feed warble tone back to the door speech unit.

The older ones have AC buzzers in and don't feed buzz back to the door.

Owain