Circuits & Schematics Telephone

Yongping Xia EDN An idle telephone line tempts designers to use its 48 V potential as a power source. However, Part 68 of the US Federal Communications Commission's telecommunications regulations states that any device that connects to the ...

In the first part we have got acquainted with the device hardware. Have considered used interfaces and reports and the general principles of work of system. Device Usage When first turned on, the device tries to initialize the SD/MMC card. First, ...

This project describes the implementation of a phone line audio and event recorder originally devised for monitoring technical support call center attendants for quality assurance purposes. Our initial objective was to have a device that digitizes ...

How many times have you wished that you recorder your recent telephone conversation? I have, many many times. So I finally decided to make this happen by using PC and a piece of hardware (powered from USB) to record audio from phone line to MP3 ...

Here is a teleremote circuit which enables switching ‘on’ and ‘off’ of appliances through telephone lines. It can be used to switch appliances from any distance, overcoming the limited range of infrared and radio remote ...

For this first Instructable, I'll show you a recent hack I made. I had a cheap malfunctioning headset and a broken cellphone (cracked screen) and I needed a reliable solution to make calls with Skype.. so I combined two ready-for-trash items in a ...