CRMT

Developer tool · Windows

See, analyze and automate
serial communication.

CRMT opens serial ports and shows traffic as text and HEX side by side — and handles everything else communication work needs in one place, from CRC calculation and auto-responses to scripted sending and AI control.

Get it free on Microsoft Store Watch the AI demo

Free
Windows 10 · 11
x86 · x64 · ARM64
15 languages

CRMT running — COM Port Explorer, String Sender and AI Assistant (Korean UI shown)

Features

Communication work, start to finish

Connect & monitor

Detects COM ports as they connect; open several at once
Per-port baud rate, data bits, parity, stop bits, flow control
Switch text/HEX views and log both formats together
Timestamps, highlighting, bookmarks, search, send markers
Visual Studio-style docking with saved layouts

Send & automate

String and HEX senders with optional CR/LF
Calculates and appends CRC/checksums as you send
Macros that auto-respond when a string is received
Transform data with a C# script before sending (SLST)
Sender target follows the active document

Analysis tools

Hex Editor — inspect and edit binary files
Hex Diff — compare two files byte by byte
Encoder — text/HEX ↔ UTF-7, UTF-8, UTF-32, Base64
Log Manager — communication, terminal and AI chat logs

AI & collaboration

AI Assistant pane to analyze logs and device behavior
MCP server — Claude Code and Codex control CRMT directly
CoTrace — share a live session by URL, with chat and remote commands
View-only or control permission per participant

Windows power tools

Wiretap — hook another process's COM traffic to monitor it
Steal mode — take over a port held by another process
Process Explorer
Built-in PowerShell terminal (ConPTY)

Testing & remote

nRF DFU Test — analyze Nordic BLE bootloader firmware updates packet by packet
TCP Communication Test — server load test with client count, repeats and delay
SSH sessions and SFTP directory browsing

CRMT × AI · MCP

"Connect to COM9 and tell me the GPS position."

Turn on CRMT's built-in MCP server and it registers itself with Claude Code and Codex. The AI finds ports, changes connection settings, sends data and interprets what comes back.

Demo: Claude working a GPS device on COM9 through CRMT

Turn it on in the MCP screen — registers with Claude Code and Codex automatically
Control tools are hidden from and blocked for AI apps on other PCs
Add, edit and remove macros through AI

Tools exposed

list_serial_ports
get_connection_status
connect_serial_port
set_serial_port_config
send_serial_data
get_serial_data
list_macros
add_macro
update_macro
remove_macro
list_data_senders
disconnect_serial_port

Integrity

CRC and checksums, appended automatically

Pick the algorithm your protocol uses and CRMT calculates it and appends it to the data it sends.

Checksum8NMEAModulo-2562's complement

CRC8ClassicMaxim

CRC16ClassicModbusXMODEMDNP

CRC32Classic

Pricing

CRMT is free

All core features — serial monitoring, sending, analysis — are free. Only server-backed features such as AI analysis and CoTrace live sharing use credits, and you pay for what you use.

Free

Serial connect, monitor, log
Senders, CRC, macros, scripts
Hex Editor, Hex Diff, Encoder
MCP AI control

Credits

AI Assistant analysis
CoTrace live session sharing

See credit pricing

Roadmap

Beyond Windows, to macOS and Linux

We're building a cross-platform version on Avalonia. It's in preview today; we'll announce a release date once it's set.

Preview in development

Local serial · TCP client
Repeated send (with CRC)
IAR Map memory analysis
C# script test runs
SSH commands · SFTP download
Saved connection profiles

Specifications

OS: Windows 10 (2004) or later, Windows 11
Architecture: x86 · x64 · ARM64
UI languages: 15 (English, 한국어, 日本語, 中文, Deutsch, Español, Français and more)
Themes: 25 (Metro and Office, dark and light)
Distribution: Microsoft Store