Build mostly successful...

[kerne]

I've finally completed building my kit after having to source a few missing parts which I've mentioned in other threads.

What works:
- All the mechanical bits and the dialer (very satisfying to dial on this btw)
- LEDs, tho one had a loose solder joint I had to fix
- Arduino boots up. I was able to update the firmware successfully and talk to the modem over serial connection no prob. Verified that the rotary dial generates the correct number _almost_ every the time.
- The Lambda and Function buttons did need a little shave on the bottom to move without binding.
- SUCCESSFULLY registered on US Mobile (T-Mobile "Light Speed"), received calls and received SMS!
- Unable to place calls or send SMS (might be waiting on a US Mobile plan change, will try again later today), ATD... returns " NO CARRIER". AT+FCLASS=? returns 0,2.0 (data, fax class 2) as the only options. There is no 8 (voice) option. AT+CREG? returns 1,6 (registered, SMS only). Will try US Mobile (Verizon "Warp 5G" and AT&T "Dark Star") later. Changing +CVMOD from VOIP to CS has no effect.

What doesn't work
- E-paper display got damaged during storage and/or assembly, but this looks like a suitable replacement (https://www.mouser.com/ProductDetail/485-4262)
- OLED doesn't show anything even after the firmware update and re-seating the connector. I'm hopeful there's a software fix for this, but if not-or if anyone needs one-this looks like a suitable replacement (https://www.mouser.com/ProductDetail/66 ... 5664AWAP3N)
- Bell doesn't ring when tested with Fn+#3
- Test tone via AT commands didn't sound from the speaker

And the weirdest item...the included micro SD card...it's labeled "128MB" but it's actually 8GB (photo attached). Also, it's empty. Can anyone share the files that are supposed to be on it?

Btw, what's the white switch on the bottom of the handset?

[zero1tango]

The tiny white switch at the bottom of the handset is a physical disconnect switch for the RUSP microphone. ...so "Big Brother" can't hear you, even when "they" tell you he's not listening (like with the Nest thermostats).

[imyxh]

Hey, congrats on the build! Sorry about the solder joint and epaper. We can send you a replacement for both that and the OLED if needed.

Unable to place calls or send SMS (might be waiting on a US Mobile plan change, will try again later today), ATD... returns " NO CARRIER". AT+FCLASS=? returns 0,2.0 (data, fax class 2) as the only options. There is no 8 (voice) option. AT+CREG? returns 1,6 (registered, SMS only). Will try US Mobile (Verizon "Warp 5G" and AT&T "Dark Star") later. Changing +CVMOD from VOIP to CS has no effect.

I've certainly run into "NO CARRIER" before, usually due to either signal strength issues or improper registration. It's odd to me that you can receive but not send calls. It's possible the transmitter is starved for power; is the battery connected? Usually USB power alone is not enough to power the transmitter.

By the way, which copy of the firmware did you update to? Justine's firmware, or the (admittedly somewhat in-progress) rewrite at https://github.com/skysedge/rusp_firmware? If it's the rewrite, the current way to test bell ringing is with the α switch.

For registration issues, sometimes you can get a better picture of what's going on by doing registration manually (+COPS) and sometimes checking +CEER (just make sure to check it before and after running the command). If you haven't seen it yet, there's a cheatsheet I wrote up ... and of course the LARA docs are great too.