How to connect a landline phone to a car

    Hello and welcome back to Spoken Word with Electronics. This week we discuss technology that should be in every garage: a mobile phone! I don't mean a cell phone. Put down that slab of glass. I mean a real cabled phone. Not long ago, such an idea was unobtainable, requiring gobs of money and a car trunk radio connection. But with a little unintended misuse of a commercial product, today's humans can now make any landline phone work in their car. This episode of SWWE, we discuss how to do this. You'll probably want to keep your own landline phone because of it. It can save millions of phones from landfills. It's only $30. And you can put it in your car!

  • I mean ANY landline phone. Even a rotary dial phone.
  • A big REAL telephone right up in your face. Any phone you want.
  • But in your car.
  • And it works.
  • It rings!
  • It makes calls and accepts them. It dials!
  • It's a phone!
  • Even better: You can even take that same landline phone to the park. You can call someone on a picnic. It's even a landline phone that works on water. I mean it can go on a boat. You can take this phone anywhere. No radio required! Instructions below. Here's this week's audio:

    So how is this done?

    The technology you'll be using to make your car phone is a product with a slightly "AS SEEN ON TV" vibe to it. But I've been working with it for about a month and now consider it one of the most well thought out devices I've encountered in over a decade. It's called Cell2Jack.

  1. Cell2Jack, at its most basic, makes any landline phone into a Bluetooth headset. But there's tons more you can do with it. It DOES require a cell phone service to operate. But the trick: It fully provides the necessary power to operate a landline phone. (See below for "Telephone Line Simulators" to see how expensive simply powering a phone without a utility connection used to cost) – This costs $30. Here's what it looks like:

    This small peripheral (about 3 by 2 inches in size) allows for 5V to run off a USB-C jack. Connecting that USB 5V in to a portable USB power supply makes this portable. You plug your landline phone through the RJ11 connector marked PHONE. The 5V out is a nice feature, but does not need to be used in setting it up for use. This, along with a Bluetooth enabled cell phone will make any landline phone portable for car use.

  2. INSTRUCTIONS: This device is designed for senior citizens to understand, so it couldn't be easier to set up. You connect power to the 5V USB-C port, and then connect your landline's phone cable to the Cell2Jack box. A red light will glow, along with a blue light when set-up is complete. Pick up the phone and the phone will speak loudly stating it is not yet connected. You then use the phone's dial (either touchpad or rotary) to enter in a three digit code. This makes the phone findable as a Bluetooth device. You then pair with your phone. From that point on, the landline phone will ring for your cell phone. You can use your landline to dial for your cell phone. And, with a portable power device like a USB power brick, you can take your landline anywhere.

    Here, I powered it through my car's USB port for a trip to the mountains:

    Free your line and your mind will follow

  3. One disclaimer for car use: Operate at your own risk! This is intended as a novelty idea and any large objects in a car should be viewed as a hazard, etc. A police officer might stop you if you are talking on a phone, too. But look how nice this looks bolted to the dashboard!
  4. I found my Cell2Jack (or C2J) on Amazon and see them on Ebay and elsewhere. About $30-40 depending on where you find one. I've seen them offered used, too. I'll link the Amazon listing here as it provides a great list of user-provided resources and answers. Contrary to Magic Jack or VOIP, there are NO ADDITIONAL FEES beyond buying the device.
  5. That NO FEE thing is really worth praising. My personal journey with Cell2Jack began looking for just a way to power my landline phone. I wanted to hear a Dial Tone whenever I picked up the handset. I first looked at VOIP to do this; it would have been about $5/month plus equipment rental with our ISP to provide a phone connection, adding up to over a $100 a year. Magic Jack currently boasts a $43 a year charge. For both that means service can be suspended if the company stops existing. And while on the toll, it can cost countless dollars over a few decades, nor are you locked into a rate. Cell2Jack has no fees beyond the equipment itself. Think about that. It's merciful.
  6. Benefit to the planet:

  7. To my best guess, Cell2Jack has been around since 2018 (at least that's when "CELL2JACK" was granted a trademark by the UPSTO) In that time, we have thrown out an estimated 600 million cell phones.
  8. That's easily 1 billion phones thrown out since the iPhone was introduced in 2007. This statistic does not even include the many millions of landline phones chunked away to the garbage, as well.
  9. The impact on our environment to manufacture new cell phones is literally murdering our planet, yet we keep making and introducing new cell phones. And we keep throwing out our old cell phones.
  10. We even mock people for having an older iPhone that runs the same software and provide the same functions. Try holding up an iPhone 7 in a party and see if you don't any side-eyes or snickers.
  11. This "Phone Exceptionalism" shaming didn't exist with landline phones because, very often, the newer landline phones sucked worse than the classic ones. Landline phones of the 1990s, if they weren't cordless, were lighter and cheaper in construction. If you went to a home with a well preserved 1960s phone, it was often praise for the solid heavy well designed item.
  12. The components crisis of the last few years should have been a halt to making any new phones, but instead we still introduce phones. People are buying phones purely for aesthetics now, as we've long exceeded the Moore's Law of what we need out of a phone to do. Now it is only what we would LIKE a phone to do. Oh, now it folds! The next innovation will be that it's back to being flat.
  13. If you haven't been fooled into throwing them out, many homes have many nice old phones (ornate, heavy, funny, or sentimental phones) and news that you can repurpose them into your cell network is likely exciting for some people reading this. I haven't yet tried this, but Cell2Jack claims you can use them together to make a network of phones off one cell phone. Talk about innovative tech!
  14. While Apple has been forced to provide right to repair, it really should never have released more than one case for the iPhone. I mean the case you bought fifteen years ago should STILL be your phone. Apple should have made everything else modular, swap out a camera, swap out a PCB. The glass screen could slide out and a replacement could slide back in. If they wanted to upsell you it could be in tinted glass or colored glass, but not an entire new phone just to have a different bevel. Stuff like that. It's not tough to do. It was a decision to make the entire phone disposable. At the very least we can repurpose our landlines.
  15. Praising Good Design

  1. Something like this is liberating. It can train you to use your cell phone less. instantly make your cell phone into a "dumb phone" as it will just function as a bridge for receiving or making calls. In emergencies, you can still use your normal phone to text. In dire emergencies, you can use it for web browsing, and in even direr emergencies, you can still use the phone for social media.
  2. the only negative is unpairing it to use your phone can take some finessing. It will ring INSTEAD of your cell phone ringing. I had to configure my phone a bit to not default to the landline, through unpairing it when I didn't want it to be in use. But maybe this default pairing is preferred.
  3. To any product designers reading this: This device requires NO APP. Please consider how nice this is. A smart device with no freakin app to be dependent upon. No software updates to a phone to make it not work. All that is required is a Bluetooth connection. Conceivably, Bluetooth might change over time, but this is far more predictable than an Apple or Android upgrade bricking your software.
  4. An app should be the LAST THING a product designer considers necessary to add to a product and too often it's sold as a feature. Instead, Cell2Jack uses the phone's keyboard (or rotary dial) to enter in commands. It's simple and it's brilliant. The inclusion of rotary for data entry is too freakin considerate. It reminds me of how much arrogance you find in software design.
  5. If you maintain that you still need to implement an app for your product, I recommend instead that you add a RCA video jack (just the yellow one) to your device. This could pair with a TV and a user could use the television to customize settings. I have a Denon amp bought years ago that did this. That older amp still works, while a later one I bought needs an APP for customizing. That app is an unsupported 32-bit app that hasn't been updated and will now not work on my phone. About 90% of most devices today could use a TV set to configure their settings but we still cheap out by enslaving them to an app.
  6. One BRILLIANT idea about Cell2Jack: It solves a problem of erratic cell phone coverage in your home. Particularly since the pandemic where many people are home using cell service, many people have lost consistent signals inside their residences. Just plug the cell phone into the wall where the signal is strong, and use your iPad or whatever other gadget for internet and zombie-ing out on social media. Cell2Jack suggests placing your cell phone where there is service and then using the landline anywhere in your home as the equivalent of a cell phone repeater. Blank spots undone!
  7. Additionally: How many cell phones have you thrown out because using them for phone conversations ruined the phone? I'm in Texas where it is constantly hot and everyone sweats onto their phones. Sweat from your face is a consistent example of something that shorts out home buttons, jams on and off switches, or even clouds the screen.
  8. You might claim recent phones are water resistant, but I claim B.S. on that. As long as there is any exposed port on the phone, salt and water will find a way. If you were talking into a phone headset INSTEAD, your phone would last longer. A phone headset from 1965 still works as designed. I have also sweat onto a landline headset. It expects you to sweat. I can replace a headset without throwing out the entire landline phone, too. But enough about all that. Let's look at some other cool uses of this cheap device.


  9. Most impressively, at least to my needs, Cell2Jack can be used to simply restore a landline back to life, with a working dial tone. I can hear a dial tone whenever I want to hear one by picking up the headset. Pick up the phone and there is that tone. You have no idea how much you might have missed this until you restore a dial tone to your home.


  10. Did you know the dial tone is actually two tones? The dial tone itself, and its curious blend of hertz, is the subject of this week's show. We deconstruct the U.S. dial tone into its two frequencies (350Hz and 440Hz) and also provide the dial tone in triangle and square wave formats. Most dial tones are in SINE. If you've never heard a dial tone in SQUARE you're really in for something. Listen to this week's show for more on the Dial Tone itself, including as a SQUARE WAVE.

    SOUND TOOL: There's also an audio application for bandpass filtering

    An impressive low-fidelity recording technique can be found by using Cell2Jack to send audio through a vintage phone. Record with a Direct Connect Telephone Record Device kind of adapter. Shown above is the adapter connected to the phone via the phone cable. Plug the adapter's TS output jack into a recorder. The Cell2Jack is powered via USB. Here, it is plugged from a USB-C cable into a USB power adapter. The Cell2Jack powers the phone. The whole thing is connected to a cheap extension cord. It's exciting to think about sending audio through the aging components of the phone. The more feedback and RF distortion the better. This is a great vocal filter for narration or distorted singing. Try it out.

    Older tech that did something similar: Telephone Line Simulators

  • Prior to finding Cell2Jack, with my goal to just bring life back to a phone with a working dial tone, I first fell in love with the idea of Telephone Line Simulators. You can find Telephone Line Simulators in use for causing a phone to ring in theater production, too. They are basically a power source connected to a landline phone with some communication pieces built into them. A lot of people like the Skutch Stuff. (That gives me an opportunity to write "Skutch Stuff") – For a long time, I was looking to get a RING-IT! which allows two phones to work together offline. I came very close to a RING-IT! but opted to not get one. And if you want to go top of the line, you can also look into the CELTONE stuff. Those are great boxes:

    The CELTONE series is considered the top of the line in 1990s-2000s. If you needed one for a trade show, you could "Rent it for $150/month". Shown above is a TLS3 I picked up used/broken. Haven't looked into fixing it, but really like the ON/RING switch.

  • I should mention here that the history for how Telephone Line Simulators exist is pretty interesting: TRADE SHOWS! Have you ever been to a trade show in a convention center? How many landline connections do you think they have in that giant room? Maybe five? And how many of those can be used by booth renters? Probably none! So: Can you imagine having a convention for phone products or Telemarketing gear? Telephone Line Simulators is how those salespersons powered their telephony equipment. This allowed a room of 500 phone based products to be shown in a trade show without any of them needing a working phone line. They'd each just need a telephone line simulator. Neat when you think about it.
  • So I was first really enamored in getting a Telephone Line Simulator. Cost becomes an issue when you're just wanting to use one to have a dial tone. All of the Telephone Line Simulators were above the $100 mark in terms of cost. High end ones cost $1500. I love a dial tone but couldn't consider anything above $50 to be justifiable. Listeners of this show might recall my dip into Phonal Tonal as an app. But none of them rang my bell so to speak (sorry for the pun). I wanted a Dial Tone on a landline phone. That was until I finally found the Cell2Jack.
  • In future episodes I plan to work more with Cell2Jack as a recording hub, too, as my old 1960's telephone has some really nicely unstable aged components and bandpass filtering, complete with artifacts and buzz. I'm still figuring out the best approach for this and will report back later with good apps that work well/filter nicely with this approach to sound design. Regards to Cell2Jack for such a smart ecologically intelligent product.

    One final thing: In Memory to Rob Hordijk

  • As indicated in the parenthesis of our show title, this week's show is dedicated to Rob Hordijk. Mr Hordijk, who very sadly passed away this month at age 64 is/was widely regarded in the synthesizer community as a paragon of good ideas. An introduction can be found in the Rob Hordijk wiki, along with this incredible wealth of documentation he constructed over decades. Modular users would often travel to the Netherlands to pick up their own Hordijk systems. Be sure to look up the Benjolin, Rungler, and the Blippoo Box. We grieve his passing and thank him for all the wonderful sound and unpredictability! (Hordijk is perhaps best known outside of modular for his contributions to Nord) – A short film by Franz Schuier via Synthtopia:

  • SWWE #75: "Dial Tone Music" (Dedicated to Rob Hordijk)

    Ethan Persoff is a sound designer based in Austin Texas. He likes lists. You can subscribe to Spoken Word with Electronics via 1) Bandcamp and 2) most podcast services.