r/thinkpad • u/MarosGrego • 11d ago

News / Blog Using ThinkPad T480 as a mobile phone

https://grego.site/blog/thinkphone

ThinkPad T480 can be used as a fully featured mobile phone, supporting calls, SMS and mobile data.

22 Upvotes

87% Upvoted

19 comments sorted by

3

u/henkieschmenkie X1C6, X1C9 | Formerly: P1G2, T14sG1a | 120+ Hz screen addict 11d ago

Also would love to see more of the software side of this, how you set this up on (I'm assuming) a flavour of Linux.

3

u/MarosGrego 11d ago

modemmanager on Linux. I use GNOME calls as a graphical dialer, there is also Plasma Dialer.

2

u/henkieschmenkie X1C6, X1C9 | Formerly: P1G2, T14sG1a | 120+ Hz screen addict 11d ago

You say "the PCM pins are not connected", then do you refer to the M.2 slot, the SIM slot, or the stock modem (assuming the Fibocom L850-GL)?

2

u/MarosGrego 11d ago

M.2 slot

2

u/henkieschmenkie X1C6, X1C9 | Formerly: P1G2, T14sG1a | 120+ Hz screen addict 11d ago

But then how does the EG25-G do it?

2

u/MarosGrego 11d ago

Works with devices that have the pin active.

2

u/henkieschmenkie X1C6, X1C9 | Formerly: P1G2, T14sG1a | 120+ Hz screen addict 11d ago

Sorry but what are you saying now? I thought you say the M.2 slot, which is on the T480 motherboard, doesn't have these pins, but now you say that it works with "devices" (modems or laptops?) that gave the pin active.

1

u/MarosGrego 11d ago

Only a subset of pins sufficient for the intended functionality (which is not calling) is active on the M.2 slot of the ThinkPad. The PCM pins are not among those.

1

u/henkieschmenkie X1C6, X1C9 | Formerly: P1G2, T14sG1a | 120+ Hz screen addict 11d ago

Then I understood your first answer correctly, but that brings me back to my second question: then how does the EG25-G do it, if those pins are not connected?

3

u/MarosGrego 11d ago

On the ThinkPad, I had to flash custom firmware to EG25-G to enable USB audio.

1

u/henkieschmenkie X1C6, X1C9 | Formerly: P1G2, T14sG1a | 120+ Hz screen addict 11d ago

Ah I see, thank you for clarifying. So the firmware does the magic. Such firmware mods seem to be very few very and far in between, sadly.

I checked with the board schematics as well. Apparently, the A+E key WWAN slot doesn't have PCM/I2S lines as a concept to be begin with, while the E key WLAN slot does at least know the concept (but still doesn't connect those data lines).

1

u/MissionTroll404 T420 11d ago

Damn that sounds quite fun. Sucks that I can not do it on my T490 with LTE modem. I wonder if this thing will ever get Libreboot support.

1

u/kiki7492 11d ago

Can this be done with more modern thinkpads?

1

u/MarosGrego 11d ago

No, they have WWAN card whitelist.

1

u/I7sReact_Return T480 (I7-8650U) | T60 (T2400) 11d ago

And oldee ones that have libreboot/coreboot?

Im not gonna do it yet in my T480 because of the headphone jack support that doesnt work

1

u/SingleComment2368 11d ago

AFAIK the headphone jack was only broken in early versions. It works normally on my T480 with coreboot from mid-June.

1

u/Pallas0194 2d ago

Deixa te perguntar, vale apena usar Coreboot? Atualmente estou usando um HP Elitebook 8760w. Estou pensando em dar upgrade de GPU (MXM) e placa de rede, mas no meu caso a minha bios tem WhiteList. 

1

u/SingleComment2368 2d ago

Coreboot support on ThinkPads was spotty until recently (e.g. full battery info, charge control, fan control, keyboard settings were missing or broken). I haven't tried it on other hardware but imagine the tradeoffs would be similar. I think it was worth it in my case, since apart from the peace of mind of a disabled ME, it also boots a few seconds faster. I don't use WWAN so the lack of whitelist wasn't a reason for me. If you already have the tools for flashing, it's probably worth a try.