Below, I will outline the first draft of the hardware needed for Autoblock. We're making landlines smart, and to do this we need to connect a processor to telecom lines. We've put together a prototype on a breadboard, and are writing code to make it all work.

This first revision uses three main stages: A Silvertel telecom module, a codec, and a Raspberry Pi. By building off of modules, we'll be able to quickly bring this product to spam-filled phone lines.

The first stage contains the Silvertel AG2130 module, the related resistors/capacitors/protection, RJ11 connectors, and a relay. The AG2130 connects to the phone line with all the proper impedance and isolation. Analog audio from the phone line is brought out to the Vin Pin, and audio can be sent to the phone line at Vout.

When the phone line rings, the "RS" pin on the module goes low. By setting the "LSC" pin high, the system can close the loop switch, accepting the phone call. With this, a processor can tell when a phone call is coming in, and can pick up the call.

A relay controls if the phone line from the wall (the station side) connects with the user's phone (the office side). When this relay is open, no signal reaches the user's phone. The exact relay, and if the relay is magnetic or optical, has not yet been decided.

A voice band codec CPC5750 digitizes the input and output analog audio from the telecom module. Audio data is sent and received from the processor using PCM, with SPI to control different setting internal to the Codec.

Finally, we have the processor for this system. Since we are using a Raspberry Pi, the schematic above is for a header that will connect to the Raspberry Pi Zero W board. The Pi connects to the Codec using SPI and PCM, and connects to the "RS" and "LSC" pins on the Silvertec module using GPIO

The Pi will be able to process dial tones/caller ID, send out the audio captcha, remember whitelisted phone numbers, run analytics, and decide what phone calls can pass though. Since we're using a Pi Zero W, we'll be able to control settings and review analytics over Bluetooth using a mobile app.

Telecom module, digitization of analog audio, and a processor. With these parts, we can make phone lines smart and finally block spam.