Yesterday at the MIT flea I happened upon this gem, a little bad boy from Wilcom called the “MODEL T303B SIGNALING SENDER.” What is it do you ask? I have no idea. What does it do? It beeps. How much did I pay for it? $7.
It’s dated 03/1983 Manufacture and appears to have been owned by GE. Here’s what I’ve been able to figure out. It’s a solid looking 10x7x7 inch box with two handles. It also has two hinges and a missing latch where a lid went at one time. On the face, it includes two lovely chrome handles and six quarter inch jacks, most of which are balanced. It includes an array of no less than 23 beautiful square push buttons. It has a rotary selector with two decimal digits labeled “SEND LEVEL (-dBm).” Along the base run 8 “one at a time” 1980s buttons. It includes one push/pull switch to turn it on, as well as a toggle switch. Lastly, a speaker and volume knob are located on the upper right of the panel. I’ve been able to get it to send signal out of one of it’s jacks.
Upon dis-assembly I’ve discovered a solid looking 1980s pcb and IC arrangement. It includes a rechargeable battery and an internal transformer for charging (classy).
Now, functionally it’s pretty interesting. Upon power up, it lights several lamps. There are three buttons labeled DTMF, MF, and DP. While Dual Tone Multi Frequency dialing is commonplace, and many can remember Dial Pulse rotary phones, this also has support for Multi Frequency dialing, which I thought was cool. This phone also has 4 additional DTMF/MF numbers, A B C and D (Autovon style).
After power up, clicking the DTMF panel has no effect, however the device stores them into memory. Pressing SEND will fire off the previously entered DTMF sequence. Selecting MF generates unrecognizeable tones and DP clicks appropriately in the appropriate sequence. There is a way to store number sequences (not that I could tell you) and recalling any unused number generates a funky techno beat.
Unfortunately the majority of this seems to be geared toward testing trunk lines. It supports E/M lines, possibly in 2 and 4 wire arrangements. Unfortunately I don’t think I’ll ever be able to test this functionality. It appears that it will connect to a regular phone line (with a 1/4 inch to modular jack adapter). I have unfortunately been unable to figure out the necessary connections as of yet. Any help would be appreciated in the comments section. It has headset ports, generically and unhelpfully unlabeled as to which is speaker or mic (or both?) :(. There is also one button that is labeled ST3P which I have yet to identify.
You can select the level of the DTMF transmission in -dBm with the retro selector. A pair of green buttons is labeled “ON HK” and “OFF HK” which appear to mean on and off hook.
The coolest feature though is the “geek magnet” factor. Nobody at the flea (or the office) has been able to walk by without poking it. It’s pretty cool. The manual is available on eBay for $40 (which is…almost 6 times more than I paid for the box itself).