Issue Getting DreamcastLive Modem to Work with Model B Modem

[jebug29]

So I bought a modem from DreamcastLive with a built-in DC-DC booster board back several months ago and just got around to testing it yesterday, sadly to no avail. After doing some testing, it seems like when it has one light on (no dialtone/command sent) it outputs a proper 12 volts to the phone line, but when both lights come on (modem is initiated), it drops down to 5 volts. This is enough to hear it over a normal telephone and in fact if a number is dialed with a normal phone while it's connected to DreamPi, it will connect and do all the nice modem sounds, but it doesn't seem like it's able to power my Model B modem. I've tried several different cables and configurations (swapping out a Pi Zero W for a Pi 3B, etc), but I just can't get it to work. I'm assuming it's a voltage issue as several people have said the DC modem won't operate on less than 9 volts (for NTSC modems), but I also am unsure about what the actual minimum voltage is considering batteries' voltage drops as it loses charge, and people seem to get quite a lot of time out of their line voltage inducers. I'm assuming the issue is either the DreamLive modem's output voltage or my Dreamcast modem, and I'm not totally sure which I can safely determine.

The DC-DC board DOES still output 12 volts even whenever the voltage on the phone line drops to 5 volts, so I'm definitely not sure what's causing the drop, unless perhaps the board could be wired a different way. Any and all help would be greatly appreciated.

Thanks!

[pcwzrd13]

What exactly is the issue you're having? What happens when you try and connect with a web browser or game?

[jebug29]

What exactly is the issue you're having? What happens when you try and connect with a web browser or game?

In PlanetWeb it says "Dialing Modem" but then just never does and gives me "There is no answer at this telephone number. Check your ISP Phone #". If I plug a phone inline and listen, there's nothing but a dial tone.

[pcwzrd13]

Ok, it sounds like it would be either a problem with the USB modem or the Dreamcast modem. The only way to know for sure is to swap one of them out. If you want to send the USB modem back to me for testing, I'm happy to do it. Just shoot me an email.

[jebug29]

Ok, it sounds like it would be either a problem with the USB modem or the Dreamcast modem. The only way to know for sure is to swap one of them out. If you want to send the USB modem back to me for testing, I'm happy to do it. Just shoot me an email.

Got it! Will let you know. Thanks!

[jebug29]

I went over to my mom's house for Mother's Day and actually managed to find an old Lenovo USB modem I had with the Conexant chipset. I hooked it up with 9v volts inline from my bench PSU and managed to get the Dreamcast online!

After my last post I tried to update the firmware on the Dell/DCLive one using the Conexant firmware from Dell's site, but it seems to have bricked it (still get a console with TeraTerm and can run AT commands, but it doesn't dial or anything), so that's my bad and I'll just keep it. I may just use the Dell one for parts to build a proper voltage inducer since it already has the step-up converter and required capacitor & resistor in it.

Thank you though! Next time I'll try and return it when I have a problem first before I start trying to fix things myself (^ ^;) It's a bad habit of mine lol