The advancement of digital radio networks has made it impossible to listen to mobile phones on conventional radio scanners. However, in the late 1990s, it was easy to monitor mobile phones on the analog ETOPS network, also known as the Extended Total Access Communication System (ETACS).
The ETACS and TACS are now obsolete in Europe, having been replaced by the Global System for Mobile Communication (GSM). In the United Kingdom, the last attack service operated by Vodafone was discontinued on May 31, 2001, and the competing service operated by Solna and then BT Cellnet closed on October 1, 2000.
The frequencies used by e-tax were 917.0125, 294.9875, and 949.9875. They could be listened to on an ordinary wideband radio scanner with a suitable antenna, such as a discone antenna. This made it very easy to listen to tax and e-tax channels, but calls could be handed off to a channel on another cell.
Some enthusiasts used a modified Motorola 4500X phone connected to a PC via the parallel printer port to decode the channel hopping, or alternatively, any CP3 phone with the basha firmware. Basia firmware allows you to scan e-tax channels and also to clone somebody else’s electronic serial number or ESN over-the-air. These were known as vampire phones back in the 1990s.
London electronic artist Robin Rimbaud, who went by the names of Scanner, used to roam the country’s capital armed with a radio scanner in a disco antenna, monitoring hundreds of frequencies for mobile phone calls. Scanner recorded these mobile phone conversations and set them to electronic abstract music. He caught out any personal information such as addresses, phone numbers, and names but managed to capture some quite haunting audio.
Some manufacturers made antennas for the scanners during this time for use in monitoring mobile phone conversations. Reporters from The Sun newspaper met Cyril Renan, a 17-year-old retired bank manager, who listened in on non-commercial radio frequencies in much the same way that some people listen to police frequencies using household radio sets. He played them excerpts from a taping recorded of the pre-1990 analog mobile phone conversations between Diana, Princess of Wales, and a close friend James Gill Bey.
By the end of the 1990s, GSM was fast becoming the world standard for mobile phone communications. 2G GSM networks replaced the analog 1G networks, and it was no longer possible to listen to mobile phone communications on a radio scanner. The e-tax network was finally closed in mid-2001 and fast became history to today’s modern 4G and 5G networks.