Ashley Rolfmore (leymoo)Sep 17, 2025

Oh my goodness. I think this is the only place on the internet nerdy enough to help me locate this info.

My parents met on a what was effectively an unofficial chat room hosted by capital radio (London). In the 1980s, Capital Radio used to leave their switchboard open at night (unintentionally, they didn’t realise it was happening) and people would call the regular radio phone and just end up in what was effectively a giant group call for Londoners late at night. (I say Londoners due to the reach of the radio rather than the phone line itself, people wouldn’t know the number unless they listened in).

I understand they changed how the phone system worked later in the 80s and closed this loophole off.

So what I’m after is…
- the nature of the switchboard that allowed this to happen - edit now answered
- what change would have blocked this later on - edit now answered
- any historic info on the period it was left open, or personal accounts - still pending, trying other social media too for this

#radio #capitalradio #phreaking #VintagePhoning #1980s #retrochatroom

Show threadDr Alice ViolettSep 17, 2025
@leymoo @vfrmedia this sounds like something you might know about? 😁
Show threadAlex@rtnVFRmedia Suffolk UK

@alicemcalicepants @leymoo

Quite likely the muitple circuits (eg 01 484 5255 with 10 lines which would be known as 01 484 5255/1 to 01 484 5255/10) ended up on something like a key and lamp unit (link below) - they can be set up to forbid the lines communicating with one another, but if the wiring change was not made it would be possible.

That might be deliberate for a radio station to get more than one caller to air at the same time without having multiple channels on the desk hybrid (those channel strips aren't cheap and its more work for the broadcast engineers) and/or all 10 keys are left active late at night with fewer staff

At some point Capital would have gone to a more modern ACD (automatic call distributor) which would have removed this loophole

https://www.britishtelephones.com/klu2a.htm

GPO - Key and Lamp Unit No's 2A and 10A

GPO - Key and Lamp Unit No's 2A and 10A

Sep 17, 2025 at 8:05pmWeb
Show threadAlex@rtnVFRmedia Suffolk UKSep 17, 2025

@alicemcalicepants @leymoo this makes some sense if you consider how a radio studio got telephone calls to air in the 80s, and what would likely be done to save on having an extra staff member to deal with the key and lamp unit - the hybrid is just a kind of "telephone" that connects to the studio mixer, and if it is left in "seized" mode all the connected lines at the key and lamp unit would be bridged.

BT wouldn't have particularly liked it, and there could even be a risk of putting the entire lot of calls to air (unless they were terminated on a hybrid at a studio not in use)

(I had to set up hybrids for the community radio station, they are somewhat cursed devices to get and keep running so this is very likely a hack someone at Capital thought up to save time/effort)

Show threadAshley Rolfmore (leymoo)Sep 17, 2025
@vfrmedia @alicemcalicepants I think the next step is for me to to find someone at capital radio at the time to verify - I’ve enlisted help outside fediverse for this part. And the one I’m holding out for - would be amazing to see if anyone remembers dialling in - I think the Capital Radio Facebook group might be the best shot for that (mainly due to generation of person dialling in)
Show threadAlex@rtnVFRmedia Suffolk UKSep 17, 2025

@leymoo @alicemcalicepants

its something the engineers would have *not* been encouraged to do (neither by BT nor the IBA), but they would have got away with it for an inbound calls only set of circuits (BT *really* would not approve of 10 circuits being seized at once for an outbound call!)

You /might/ get a retired broadcast engineer confessing to it but some are still in employment so might not fess up to this having happened.

Global and Bauer are still very protective of their infrastructure - even recently they tasked Arqiva to look at old infrastructure for Radio Orwell Ipswich and noticed the community radio transmitter in the hospital plant room (which I helped install), although Arqiva were impressed with what we had achieved (and we have a fraction of their budgets!)

Show threadAshley Rolfmore (leymoo)Sep 17, 2025
@vfrmedia @alicemcalicepants ah, that tracks but a mild shame. I suspect trying to get hold of anyone who remembers dialling in is an easier shot.
Show threadAlexander BochmannSep 17, 2025

@leymoo I know nothing of this but did some bored web searching, and there's at least one passing mention of something like this on the "Original Capital Radio" facebook group (which strangely is public): https://www.facebook.com/groups/2493776779/posts/10159533720801780/?comment_id=10159534124571780

"In the 1970's we had crossed lines galore when it was 01-388-1255 and chatting with other listeners!"

(There's also some discussion of who did what to sneak into their telephone competitions in other threads there...)

@vfrmedia @alicemcalicepants

Huw Cleaver

In the 1970's we had crossed lines galore when it was 01-388-1255 and chatting with other listeners!