T-Modem s1224

PacketRadio80·T-Modem-s1224·hardware/kicad/t-modem-s1224/t-modem-s1224.kicad_pcb

About the T-Modem s1224 PCB

T-Modem s1224 is an open source RP2040/RP2350 PCB design by PacketRadio80, published on GitHub under the GPL-3.0 license. It is a 2-layer board measuring 180 × 180 mm, with 13 components from 9 distinct parts.

Its main chip is the RPi-Pico, from the RP2040/RP2350 family. By type, the board carries 1 IC, 1 transistor, 1 fuse and 1 switch.

It belongs with the rf & radio designs in this gallery.

From the project

T-Modem: A half-TNC Packet Radio Device without Modem Chip

Same PCB base as T-Modem-c1224, softmodem stuffing / metadata variant.

Keep: U1 Pico · JDC / UREG / DOR1 / F1 / CBULK / CBYP / CIN · JAF · Q1 / RPTT · JLCDI2C / ULVL / RV2 · JUSB / JUSBPICO · LED / RLED · SW1 / TP_BOOTSEL · H1–H4.

Tracks (segment): 0 — stripped 2026-08-03 for clean re-route.

- GP6 PWM AFSK out → AFTX → radio inject - GP26 ADC0 ← AFRX ← radio RX AF - GP9 PTT → PTTDRV`

Main components on the T-Modem s1224

RPi-Pico

T-Modem s1224 bill of materials (BOM)

13 components, 9 distinct parts — part numbers from the project's BOM.

Qty	Part	Footprint	Refs
1	RPi-Pico	RaspberryPi_Pico_Common_THT	U1
1	2N2222A	TO-92	Q1
2	100nF	C_Disc_D5.0mm_W2.5mm_P5.00mm	C_BYP1, C_BYP2
1	1N5819	D_DO-41_SOD81_P10.16mm_Horizontal	D_OR1
1	MF-RG500	Fuse_Bourns_MF-RG500	F1
1	LCD I2C	PinHeader_1x04_P2.54mm_Vertical	J_LCD_I2C
1	10k contrast	Potentiometer_Bourns_3296W_Vertical	RV2
4	1k	R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal	R_LED1, R_LED2, R_LED3, R_LED4
1	BOOTSEL	SW_PUSH_6mm	SW1

T-Modem s1224 design files

The KiCad project lives in the PacketRadio80/T-Modem-s1224 repository on GitHub; these links point at the commit this page was built from.

T-Modem s1224: common questions

What microcontroller does the T-Modem s1224 use?

The T-Modem s1224 is built around the RPi-Pico, from the RP2040/RP2350 family.

How big is the T-Modem s1224 PCB?

The T-Modem s1224 measures 180 × 180 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the T-Modem s1224?

13 components, from 9 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.

Where can I download the T-Modem s1224 design files?

From the PacketRadio80/T-Modem-s1224 repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.

Can I use the T-Modem s1224 design in my own project?

Yes, under the terms of its GPL-3.0 license, which PacketRadio80 chose for the repository.

Can I test firmware for the T-Modem s1224 without the hardware?

Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug RP2040/RP2350 firmware against it before you order a PCB.