Somewhere around the nineties, there was a trend to have colorful lights attached somehow to cellular phones. Found one. Instructions say to insert on the antenna jack, for brands such an such. Supposed to turn on when ringing...
What does / did ringing have to do with the antenna ? Transmission / reporting to cell is not ring related.

 

They typically did light up any time the phone talked to the network, but logistical comms (registration, handoffs, power control) packets were so short that people didn't notice it.

I always had to shake my head at these things. People would complain about limited battery life (which was a much bigger issue back then) and yet hang this crap on their phones that did nothing but shorten the battery life.

Even better were the devices that claimed to "shield" people from the "brain-damaging radiation" from their cell phone, but which typically only served to partially block the signal forcing the phone to increase its transmit power to compensate, thus exposing the person to that much more radiation.

 

Based on the way some of those folks who constantly have the phone glued to their head, it certainly looks like there has been some damaging effect has happened., contrary to whatever claims made by self proclaimed experts. Of course, it may not have been the close RF exposure that produced the condition.
As for the phone lights, some phones were made with features that allowed additional accessory power. That may even have included external amplifiers intended for non-US markets.

 

Consider also that current cellphones are FIVE GENERATIONS DIFFERENT from those first generation cell phones.. NOTHING IS THE SAME!! So the toys that may have worked for some of the GEN ONE phones have no way to connect to current phones.

 

Somewhere around the nineties, there was a trend to have colorful lights attached somehow to cellular phones. Found one. Instructions say to insert on the antenna jack, for brands such an such. Supposed to turn on when ringing...
What does / did ringing have to do with the antenna ? Transmission / reporting to cell is not ring related.

In fact, anything that would make your computer speakers make the iconic cell phone sound would cause it to light, it wasn't just ringing. The sync with ringing was because the phone is commanded to ring by the cell site in a consistent, high overhead way.

The devices are dead stupid—a battery, a transistor, and an LED.