Don't see your modem listed? Adding support starts with a HAR capture from your modem's web interface. This guide walks you through capturing and submitting it. From there, a maintainer or contributor builds a parser, and you verify it works on your hardware before it ships.
This guide is for Home Assistant users who want to request support. If you're comfortable with AI tools and want to help move things faster (analyze the capture yourself, propose a catalog entry, help triage issues), see the AI-assisted catalog contribution guide in CONTRIBUTING.md instead.
- Downstream/upstream channel data (frequency, power, SNR)
- Error counts (corrected/uncorrectable codewords)
- Connection status and DOCSIS lock state
- System information (firmware, uptime)
WiFi settings, router configuration, device lists, account information.
Install har-capture and run it against your modem's IP:
pip install "har-capture[full]"
har-capture 192.168.100.1 --patterns network-device--patterns network-device selects the PII rule set for routers and
modems. Replace 192.168.100.1 with your modem's IP if it differs.
If your modem requires HTTP Basic Auth, add --username and
--password flags — see
har-capture's CLI reference
for details.
A few cable-modem-specific tips:
- During capture, log in if needed, visit all status pages, and wait 3–5 seconds per page for async data to load before closing the browser. har-capture launches its own controlled chromium instance, so there's no need to use your regular browser's incognito mode — each capture starts from a clean session.
har-capture produces a sanitized, gzipped .sanitized.har.gz file —
that's the artifact to attach in Step 3.
har-capture automatically redacts MAC addresses, serial numbers,
public IPs, and known credential patterns — but it's best-effort. Some
modems embed WiFi credentials in unlabeled JavaScript or proprietary
blobs the sanitizer hasn't seen. Pick one of these to verify before
sharing:
- AI-assisted self-screen (faster) — paste a prepared prompt into ChatGPT, Claude, or any AI assistant that takes file attachments. Full prompt and instructions: docs/examples/har-pii-screen-prompt.md.
- Manual checklist (5 minutes) — open the file in a text editor and search for a short list of patterns: docs/examples/har-pii-manual-checklist.md.
If anything sensitive remains, replace it with ***REDACTED***, save,
re-gzip, and note what you redacted in your issue so the sanitizer
can be improved for future contributors.
Open the Modem Request issue template and:
- Fill in modem details (model, manufacturer)
- Attach your
.sanitized.har.gz - If you ran the AI screen, include the output block in your issue
- Note any manual redactions you made
| Data type | What happens |
|---|---|
| WiFi credentials | Auto-redacted; verify before sharing |
| MAC addresses | Auto-redacted (hashed, format 02:xx:xx:xx:xx:xx) |
| Serial numbers | Auto-redacted (hashed, SERIAL_* prefix) |
| Public IPs | Auto-redacted (240.x.x.x reserved range) |
| Channel data (power, SNR) | Preserved — needed for parser |
| Firmware version | Preserved — useful for compatibility |
| Uptime | Preserved — useful for testing |
Modem IPs like 192.168.100.1 are preserved — they're standard
defaults, not personal information.
- Browse existing modem request issues for examples
- See the modem catalog for currently supported modems