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Dialing Up the Past
December 30, 2024
Remember the sweet sound of a dial-up modem connecting to the internet? Brrrzzzzzt... kssshhh... Beeeeep! Ah, those were the days. Back in the 1990s, US Robotics was the king of the dial-up world, and their 56K modems were the gateway to the digital frontier. The US Robotics 5686 is a little newer, born in the early 2000s, but what lurks beneath its black exterior? Let's crack this bad boy open and take a peek!
The US Robotics 56K v.92 External Faxmodem in all it's glory
Teardown Time
We'll need a trusty screwdriver, maybe a spudger or two, a healthy dose of curiosity and maybe a dust mask, who knows what we'll find in there! After removing just two exposed screws on the bottom front we can feast our eyes on the internal circuitry. The best part so far? No plastic clips, no spudger needed!
The US Robotics 5686 modem mood ring
Check out those LEDs! The modem has a whole light show going on. From left to right you've got your auto answer, carrier detect, receive and send indicators, terminal ready, clear to send and error control / fax activity light... it's like a miniature Christmas tree. These little LEDs give you a quick glimpse into what the modem is up to, kind of like a mood ring for your dialup connection.
Chip Safari
Now for the fun part: identifying the chips that make this modem sing its dial-up song. We're likely to find a processor, data dump, data access arrangement (DAA) to provide the hardware interface to the phone line, some memory and a space for storage and a few other components. Let's see if we can spot the stars of the show!
U4 - AM29F200BB-90SI Flash
Contains stored settings
U7 - Si3021-KS
Telephone Line Interface
U8 - Si3012-KS
Telephone Line Interface
U13 - SN75196
RS-232 Driver / Receiver
Shhh... It's a Secret! (The DIP Switch Edition)
Hidden on the back, you'll find a row of DIP switches. These aren't just any ordinary switches; they're like cheat codes for your modem. Flip the right ones, and you can unlock hidden features and customize your experience!
Feeling brave? You can dive into advanced settings like auto-answer suppression, carrier detect override, and software defaults. It's like having your own secret laboratory for your dialup connection! For those daring enough to explore the full potential of these DIP switches, we've got the decoder ring on the bottom of the modem, or for more detail, see the feature page here.
DIP switches on the rear of the modem
The secret decoder ring
Testing, Testing... 1, 2, 3
Forget about finding a working phone line (who even has those anymore?). We're going old-school hacker style and using a serial terminal to communicate with our modem. Dust off that serial cable (or USB-to-serial adapter), fire up your favorite terminal software (PuTTY, anyone?), and get ready to unleash some AT commands.
First, let's make sure our modem is awake and listening. We'll start with the classic AT command, followed by ATZ to reset the modem. If we get an OK response, we're in business!
We can then follow that with ATI7 to get some product information from the modem. Very interesting! Looks like this one likely left the factory in 2024.
ATI4 spills the beans on the modem's current configuration, showing us all the settings and parameters that control its behavior. It's like peeking under the hood to see what makes this beast tick. The details of the S-Register meanings can be found here.
The modem can also be internally tested using an assortment to AT&T# commands.
AT&T1 performs an analog loopback test, which can be interrupted by the escape sequence +++, and then finally AT&T0 to end testing. ATH sends the hang-up command to the modem.
With these AT commands, we can test our US Robotics 5686 modem and ensure it's ready for action (or at least ready to sit on a shelf and look pretty). Who needs a phone line when you have the power of the command line?
Final Thoughts
Well, there you have it! We've journeyed into the heart of a US Robotics 5686 modem, uncovering its secrets and marveling at its inner workings. It's amazing to think that this little black box once held the key to connecting us to a world of information and possibilities at a blazing (for the time) 56K speed.
I don't know about you, but those dial-up sounds bring back a flood of memories. Growing up, the symphony of beeps and boops was the soundtrack to my online adventures. From exploring the depths of BBSes to downloading (very slowly) the latest shareware games, that 56K connection felt like a rocket compared to the 1200 bps modem I started with on my trusty Commodore 64. Ah, the good old days!
It's incredible how far technology has come since then. Today, we have lightning-fast internet speeds, Wi-Fi connections that blanket our homes, and devices that fit in our pockets with more processing power than a roomful of vintage computers. But there's something special about revisiting these retro relics, like this US Robotics modem. They remind us of how far we've come and offer a glimpse into the ingenuity and creativity that paved the way for today's digital world.
So, the next time you hear that familiar dial-up tone, take a moment to appreciate the journey. From humble beginnings to high-speed connections, modems like this US Robotics 5686 and its dial-up brethren played a vital role in shaping the internet as we know it. And who knows, maybe one day we'll look back on our current technology with the same sense of nostalgia and wonder.
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