rotary dialling

2 Articles

Rotary Phone Gets Bluetooth Upgrade

May 4, 2019 by 7 Comments

Rotary dial phones have a certain romantic charm about them; something never quite captured in the post-Touch Tone era. With landline phone services less popular than ever, these old workhorses aren’t really cut out for daily use anymore. However, with a modern brain transplant, they can still get the job done just fine.

[Xabier Zubizarreta] has undertaken to retrofit his FeTAp-611 rotary phone with a Bluetooth rig, allowing it to be used with smartphones to place and receive calls. A Raspberry Pi Zero W serves as the brains of the operation, chosen for its compact size and onboard Bluetooth and WiFi. Getting the Pi to work effectively with an Android phone as a Bluetooth audio device requires some trickery, but it’s nothing that can’t be fixed by custom compiling a few off-the-shelf tools. [Xabier]’s next big hurdle is finding a tidy way to generate a 30 VAC signal to drive the original ringer, something that proves difficult for most similar projects.

We love to see these telecommunication relics kept ticking, so if you happen to be building a vintage telephone exchange in your garden shed – be sure to let us know.

This Vintage Phone Goes Cellular

February 5, 2019 by 8 Comments

Way back in the good old days, life ran at a slower pace. It took us almost a decade to get to the moon, and dialling the phone was a lazy affair which required the user to wait for the rotary mechanism to rewind after selecting each digit. Eager to bring a taste of retro telephony into the modern era, [Marek] retrofitted this vintage Polish telephone with a GSM upgrade.

The phone [Marek] salvaged had already been largely gutted, so there was little to lose in the transformation. A Motorola D15 GSM module was sourced from an alarm system to provide a network connection to the project. An Atmega328 was then used to translate the rotary dial mechanics into something more usable by the cellular module.

Attention to detail can really make a project shine, and [Marek] didn’t skimp in this area. The original ringer was rewound to operate with a half H-bridge at a lower voltage more suitable to the modern electronics inside. The microcontroller also helped out by using its PWM hardware to simulate a dialtone and the characteristic sound of pulse dialling.

It’s always nice to see retro hardware given a new lease on life. Unfortunately, GSM networks aren’t long for this world, so a further update may be required before long. These old phones have plenty of potential, as we’ve seen before.