![\"\"](\"http:\/\/images.amazon.com\/images\/P\/B00005NGR6.01.LZZZZZZZ.jpg\" "\\"GE")
<\/a><\/p>\nThere are two ways to practically\u00a0interface\u00a0my computer to the phone. The cleanest solution is to make a device that allows me to convert the audio input\/output to\/from the computer to a telephone line signal. I did some research (ie, Googled), and didn’t find enough information to help me (not that it doesn’t exist, I just didn’t find it). There are many commercial options, but most of them are designed to work with particular software (ie, just Skype) whereas I wanted more flexibility. I opted then for the dirtier route: audio injection.<\/p>\n
The idea behind this is simple: open up the base, find where the audio signal pins are on the RF (radio frequency) module, and connect wires to those pins that allow me to connect my computer to it (headphone jacks). In order to find these pins, I went through the following process:<\/p>\n
Initial Setup (Disclaimer)<\/span><\/p>\n Before we go too far: I am not responsible for anything that results from your decision to follow this write-up, including but not limited to property damage, fire, injury, or death.<\/strong><\/p>\n Here are some risks of damage:<\/strong><\/p>\n Having said that, here are some important considerations:<\/p>\n My setup for probing was simply that: the DC adapter plugged into the wall, and nothing more.<\/p>\n Finding the Phone’s Microphone<\/span><\/p>\n This step may have been the more difficult of the two, but I was lucky: the board had a single IC on it: KA8532. After reading through the datasheet<\/a> (PDF download) for this chip, I discovered that the\u00a0audio\u00a0output is on pin 14. This made probing with my oscilloscope a lot easier. I pressed Talk on the phone,\u00a0and\u00a0put my probe on that pin: silence. Then I spoke, and saw my voice on the oscilloscope display: can it really be so simple?<\/p>\n Finding the Phone’s Speaker<\/span><\/p>\n I say that this was easier because I took the brute force method. I grabbed an old mp3 player I didn’t care about being damaged, stripped the ends of some headphone cable, hit play and simply touched different pins on the interfacing connector between the main PCB and the RF module, and waited to hear music on the phone. Once I did, I knew that was the right pin!<\/p>\n Make the Connection<\/span><\/p>\n I scrounged through my wire bucket and found two headphone cables: one for the microphone and one for the speaker. I soldered the wires in place to the pins I discovered.<\/p>\n At this point, I connected the two cables to the computer, and hit Talk. The phone tried… and failed to connect. I was confused, but only slightly. I disconnected the base from the computer and tried again: it now worked. I believe that I may have connected my speaker wire to a pin that also controlled something to do with the RF communications. By plugging it in before the connection is established, it may create noise that makes connection impossible. So to make a call, first I hit Talk, then I plug it to the computer.<\/p>\n\n
\n
<\/a><\/p>\n