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Handheld & Portable Device Support

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NTG edited this page May 29, 2026 · 4 revisions

🚧 WORK IN PROGRESS!!! 🚧

Important

This guide covers handheld and portable devices (Steam Deck, ROG Ally, etc.) and their specific adapter chains for CRT output. For standard PC installation, see How to v43.

Supported Handheld Devices

Modern handheld gaming devices support DisplayPort Alt Mode over USB-C, which allows CRT output via an appropriate adapter chain.

Devices with Confirmed Support

  • Steam Deck (all revisions)
  • ASUS ROG Ally (and Ally X)
  • Other DP Alt Mode USB-C devices (may work—report results to Discord)

Adapter Chain Requirements

All handheld devices require a two-step adapter chain for CRT output:

  1. USB-C → DisplayPort adapter (required—provides DP Alt Mode)
  2. DisplayPort → VGA DAC (required—converts to analog 15kHz signal)
  3. VGA → CRT input adapter (optional—depends on your CRT's input type)

⚠️ Important: A single USB-C → VGA adapter will NOT work. You must use both adapters in sequence. DisplayPort Alt Mode must be the first step.

USB-C → DisplayPort Adapters

Choose an adapter that supports DisplayPort Alt Mode and ideally includes a USB-C Pass-Through port for charging while using CRT output.

Caution

While USB-C to DisplayPort adapters support DP Alt Mode and work well for CRT output, some USB-C hubs with DP Alt Mode may have issues passing stable low dot-clock paths required for CRT timings.

Docks with dual video outputs have been unsuccessful (such as Steam Deck Docking Station & M.2 Steam Deck Dock). Additionally, USB-C Pass-Through ports cannot be used to transfer USB data, however a non-Pass-Through port can be used with another USB hub to expand I/O ports.

For best results, use the recommended adapters listed below.

Tested & Recommended USB-C to DisplayPort Adapters

  • StarTech.com - CDP2DP14UCPB

    • StarTech USB-C to DisplayPort Adapter
    • DisplayPort Alt Mode compatible
    • No additional USB/Ethernet ports
    • Note: You'll need Bluetooth controllers and rely on WiFi for connectivity

  • BolAAzuL Multiport Adapter Dock

    • BolAAzuL USB-C Dock
    • DisplayPort Alt Mode compatible
    • USB 2.0 port (expandable with additional hub)
    • USB-C Pass-Through for charging

  • Cable Matters USB-C Multiport

    • Cable Matters USB-C Multiport
    • DisplayPort Alt Mode compatible
    • USB 2.0 × 2
    • 1 GB Ethernet
    • USB-C Pass-Through for charging

  • Cable Matters 8-in-1 Dock

    • Cable Matters 8-in-1 Dock
    • DisplayPort Alt Mode compatible
    • USB 3.2
    • USB 2.0
    • USB-C 3.2
    • 1 GB Ethernet
    • microSD card reader
    • SD card reader
    • USB-C Pass-Through for charging

DisplayPort → VGA DACs

The DAC converts the digital DisplayPort signal to analog VGA suitable for 15kHz CRT displays.

Requirements

Must include Realtek RTD2168 or RTD2166 chip for proper 15kHz support.

Tested & Recommended DP to VGA DACs

Final Connection: VGA to CRT Input

The last adapter in your chain depends on your CRT monitor's input type.

VGA Input (Direct Connection)

  • VGA input → Direct VGA cable (no additional adapter needed)

Legacy CRT Inputs

  • SCART input → VGA to SCART adapter/cable
  • Component (YPbPr) input → VGA to Component transcoder
  • S-Video or Composite input → VGA to S-Video/Composite transcoder

📚 For detailed information on recommended adapters, sync solutions, and transcoders, see:
Recommended Adapters, Sync Solutions & Transcoders

Complete Adapter Chains

Example 1: Steam Deck → VGA CRT (Direct)

Steam Deck USB-C
  → [StarTech CDP2DP14UCPB](https://www.amazon.com/dp/B084DW7MJ2) (USB-C to DisplayPort)
  → [Cable Matters DP to VGA](https://www.amazon.com/dp/B005H3Q56I) DAC
  → VGA cable
  → CRT (with VGA input)

Status: Works. Slight resolution-switch delay (typical of DP/USB-C DACs).

Example 2: Steam Deck → SCART CRT

Steam Deck USB-C
  → [StarTech CDP2DP14UCPB](https://www.amazon.com/dp/B084DW7MJ2) (USB-C to DisplayPort)
  → [Cable Matters DP to VGA](https://www.amazon.com/dp/B005H3Q56I) DAC
  → VGA to SCART adapter
  → SCART cable
  → CRT (with SCART input)

Example 3: ROG Ally → Component CRT

ROG Ally USB-C
  → [Cable Matters USB-C Multiport](https://www.amazon.com/dp/B06Y5N3YCD) (USB-C to DisplayPort)
  → [CableDeconn DP to VGA](https://www.amazon.com/dp/B0192Y9XSE) DAC
  → VGA to Component transcoder
  → Component cables
  → CRT (with Component input)

Performance Notes

  • Mode-switch delay: DisplayPort → VGA DAC chains typically have a small mode-switch delay compared to native VGA or DVI-I outputs
  • Resolution changes: During in-game resolution switches, expect a brief pause while the DAC synchronizes
  • Typical behavior: Similar to professional external DACs; not as immediate as direct analog outputs

Sanity Check

If you want to verify your chain works, try a game with frequent resolution changes:

  • Tekken 3 (switches between different arcade resolutions during menu/gameplay)
  • MAME (if available in your setup)

A slight delay during resolution changes is normal and expected.

Steam Deck-Specific Information

Video Output Names

  • eDP-1 = Steam Deck built-in display (Wayland HD Mode)
  • DP-1 = USB-C output via DisplayPort adapter (X11 CRT Mode)

Do NOT Select

  • DO NOT select eDP-1 for your CRT output during installation
  • eDP-1 is always your built-in screen; it cannot be redirected to USB-C

Troubleshooting

No Video Output on CRT

  1. Verify the USB-C → DisplayPort adapter is properly connected and recognized
  2. Check that the DisplayPort → VGA DAC shows any indicator lights or signs of power
  3. Try a different USB-C port on your handheld device
  4. Confirm your CRT input type matches your final adapter

Black Screen During Boot or Mode Switch

  1. Ensure your CRT is powered off during the boot sequence
  2. Wait 1 minute after boot before turning on the CRT
  3. If using a dual-boot device (Steam Deck), verify you're in X11 mode (CRT), not Wayland

Intermittent Signal Loss

  • This may indicate a weak DP Alt Mode connection
  • Try a different USB-C adapter that's known to support stable low-dot-clock output
  • Some USB-C cables are not DP Alt Mode compatible—try a different cable if available

Adapter Compatibility Issues

  • If you don't see the DAC detected, verify your USB-C port is not faulty by trying a different port
  • Make sure the USB-C cable supports DP Alt Mode (not all USB-C cables do)
  • Try the adapters in a different order or on a PC to verify they work independently

Purchase Links Summary

Adapter Type Product Amazon Link
USB-C → DP (Recommended) StarTech CDP2DP14UCPB Buy on Amazon
USB-C → DP (Alternative) BolAAzuL Multiport Buy on Amazon
USB-C → DP (With Ethernet) Cable Matters USB-C Multiport Buy on Amazon
USB-C → DP (Full Featured) Cable Matters 8-in-1 Dock Buy on Amazon
DP → VGA DAC (Recommended) Cable Matters DP to VGA Buy on Amazon
DP → VGA DAC (Alternative) CableDeconn DP to VGA Buy on Amazon

Next Steps

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