FIELD REFERENCE 33 / DISPLAY ADAPTERS
Start at the source.
Follow the direction.
DisplayPort to HDMI and HDMI to DisplayPort are different paths. These three documented examples separate the signal route, conversion requirements and power connection before you check the requested display mode.
01 / DIRECTION BEFORE DETAILS
Three paths. No universal converter.
All three examples below are StarTech.com models. They illustrate documented requirements, not purchasing recommendations, independent tests or limits for every adapter in the same class. Direction lanes are text-based reading aids, not connector drawings.
Active / EXACT-MODEL EXAMPLE
Active DisplayPort to HDMI
Documented DP-source to HDMI-display path; reverse operation is not established.
- Source requirement
- DP++ is not required by this named adapter.
- Separate power check
- No separate USB lead is listed in this sheet. This is not a general rule about active adapters or a quantified power specification.
- Stated display mode
- 3840 × 2160 at 30 Hz
This model lists no HDR support.
Evidence and exact scope
An active DisplayPort-to-HDMI converter translates a DisplayPort source for an HDMI display; direction is product-specific. C043A
Consumer identification / documented standard or product class only
The DP2HD4KS manufacturer sheet identifies an active DisplayPort-input to HDMI-output adapter and lists both DP++ and non-DP++ sources in its host-compatibility scope. C043B
DP2HD4KS only; supported direction and source class, not approval of any particular host or display.
DP2HD4KS is specified for 3840 x 2160 at 30 Hz; its performance table lists no HDR support. C043C
Exact DP2HD4KS model, not all active adapters. The broad claim that all 4K DP-to-HDMI conversion requires an active adapter is not adopted.
S035 · StarTech.com PDF ↗ · Observed 13 October 2026
Read the active DP-to-HDMI reference →Passive / EXACT-MODEL EXAMPLE
Passive DisplayPort to HDMI
Documented DP-source to HDMI-display path; not a reverse HDMI-source solution.
- Source requirement
- DP++ HDMI/DVI pass-through is required at the source.
- Separate power check
- The sheet lists DP and HDMI connections, not an auxiliary USB connection. Passive does not mean that all internal electrical behavior is documented.
- Stated display mode
- 3840 × 2160 at 30 Hz
This model lists no HDR support.
Evidence and exact scope
The cited passive DisplayPort-to-HDMI adapter class requires a DisplayPort dual-mode (DP++) source; the DP2HDMI2 manufacturer document states that requirement. C044A
Manufacturer-documented passive DP++ adapter class; not every adapter, reverse conversion, universal resolution, audio support or device compatibility.
DP2HD4KADAP is listed as passive, with a DisplayPort input and HDMI output; its source must support DP++ HDMI/DVI pass-through. C044B
Exact DP2HD4KADAP; an unknown source feature remains unknown, not a compatibility result.
The passive DP2HD4KADAP sheet lists 3840 x 2160 at 30 Hz and no HDR support. C044C
Exact-model counterexample to a universal active-for-4K rule. No claim that all passive adapters or all DP++ sources support this mode.
S634 · StarTech.com PDF ↗ · Observed 13 October 2026
Read the passive DP-to-HDMI reference →Active / EXACT-MODEL EXAMPLE
Active HDMI to DisplayPort
Manufacturer explicitly says one-way HDMI source to DisplayPort display.
- Source requirement
- An HDMI video source; use the exact requested mode at both endpoints.
- Separate power check
- Attached USB-A power lead; manufacturer specifies 5 V DC. Follow the exact accessory instructions, not a guessed power requirement.
- Stated display mode
- 3840 × 2160 at 60 Hz
Both endpoints must support the stated resolution and refresh rate. Feature combinations still need checking.
Evidence and exact scope
An HDMI-source to DisplayPort-display path needs a converter designed for that direction; example products use active conversion and auxiliary USB power. C045A
Consumer identification / documented standard or product class only
128-HDMI-DISPLAYPORT is explicitly one-way from an HDMI source to a DisplayPort display. Its attached USB-A lead is described for power, and the power table specifies 5 V DC. C045B
Exact 128-HDMI-DISPLAYPORT. USB connector-type metadata does not establish a USB video-data transport; no generic power demand or charging function inferred.
128-HDMI-DISPLAYPORT lists 3840 x 2160 at 60 Hz; its notes require both source and display to support that resolution and refresh rate. C045C
Exact-model stated mode, not independent measured performance, unrestricted HDR/color-mode support or a guarantee for a chain of converters.
S036 · StarTech.com PDF ↗ · Observed 13 October 2026
Read the active HDMI-to-DP reference →02 / KEEP THE CONDITIONS ATTACHED
Compare requirements, not labels.
| Documented example | Video direction | Source prerequisite | Listed mode and remaining limit |
|---|---|---|---|
| DP2HD4KSActive | DisplayPort output → HDMI input | DP++ is not required by this named adapter. | 3840 × 2160 at 30 Hz This model lists no HDR support. |
| DP2HD4KADAPPassive | DisplayPort output with DP++ → HDMI input | DP++ HDMI/DVI pass-through is required at the source. | 3840 × 2160 at 30 Hz This model lists no HDR support. |
| 128-HDMI-DISPLAYPORTActive | HDMI output → DisplayPort input | An HDMI video source; use the exact requested mode at both endpoints. | 3840 × 2160 at 60 Hz Both endpoints must support the stated resolution and refresh rate. Feature combinations still need checking. |
03 / ONE MISSING FACT AT A TIME
Choose the next document to check.
I have two ports to connect.
Write down the device models, which port sends video and which input the screen uses. Then read the corresponding documented path above.
Identify the display connector forms →I have a passive adapter.
Find an explicit DP++ statement for the exact computer, graphics output or dock. Do not substitute the physical DisplayPort shape for that statement.
Read the passive example →The screen says no signal.
Check direction and any required converter power first. Then compare the selected input and requested display mode with the exact manuals. This is a documentation check, not a diagnosis.
Separate USB power from video →My computer uses USB-C.
Start with the existing USB-C video requirements. USB-C shape alone does not establish the required transport, and driver-based USB graphics is a different path.
USB-C to HDMI requirements → · USB-C to DisplayPort requirements →04 / COMMON QUESTIONS
Separate the promises.
Can I reverse the same adapter?
Do not infer that from the two ends. The HDMI-to-DisplayPort example is explicitly one-way. Match the computer output to the documented input and the screen input to the documented output.
Evidence and exact scope
128-HDMI-DISPLAYPORT is explicitly one-way from an HDMI source to a DisplayPort display. Its attached USB-A lead is described for power, and the power table specifies 5 V DC. C045B
Exact 128-HDMI-DISPLAYPORT. USB connector-type metadata does not establish a USB video-data transport; no generic power demand or charging function inferred.
An active DisplayPort-to-HDMI converter translates a DisplayPort source for an HDMI display; direction is product-specific. C043A
Consumer identification / documented standard or product class only
What needs DP++?
The named passive DP2HD4KADAP requires DP++ at the source; the named active DP2HD4KS also accepts sources without DP++. Read the computer or dock documentation. A missing statement stays unresolved.
Evidence and exact scope
The DP2HD4KS manufacturer sheet identifies an active DisplayPort-input to HDMI-output adapter and lists both DP++ and non-DP++ sources in its host-compatibility scope. C043B
DP2HD4KS only; supported direction and source class, not approval of any particular host or display.
DP2HD4KADAP is listed as passive, with a DisplayPort input and HDMI output; its source must support DP++ HDMI/DVI pass-through. C044B
Exact DP2HD4KADAP; an unknown source feature remains unknown, not a compatibility result.
Does 4K always require an active adapter?
No universal rule is supported here. Both named DP-to-HDMI examples list 3840 × 2160 at 30 Hz, although one is active and one passive. The active sheet’s broader 4K wording is not promoted into a rule.
Evidence and exact scope
DP2HD4KS is specified for 3840 x 2160 at 30 Hz; its performance table lists no HDR support. C043C
Exact DP2HD4KS model, not all active adapters. The broad claim that all 4K DP-to-HDMI conversion requires an active adapter is not adopted.
The passive DP2HD4KADAP sheet lists 3840 x 2160 at 30 Hz and no HDR support. C044C
Exact-model counterexample to a universal active-for-4K rule. No claim that all passive adapters or all DP++ sources support this mode.
Does the USB lead carry this video?
For 128-HDMI-DISPLAYPORT, the source describes USB-A as the power connection and HDMI as video input. The connector-type data-rate label is not evidence of USB graphics transport.
Evidence and exact scope
128-HDMI-DISPLAYPORT is explicitly one-way from an HDMI source to a DisplayPort display. Its attached USB-A lead is described for power, and the power table specifies 5 V DC. C045B
Exact 128-HDMI-DISPLAYPORT. USB connector-type metadata does not establish a USB video-data transport; no generic power demand or charging function inferred.
Why is a 4K label not enough?
Keep resolution and refresh together, then check the required HDR, color, audio and content-protection combination across the exact devices and cables. These examples are not a timing calculator or tested compatibility list.
Evidence and exact scope
DP2HD4KS is specified for 3840 x 2160 at 30 Hz; its performance table lists no HDR support. C043C
Exact DP2HD4KS model, not all active adapters. The broad claim that all 4K DP-to-HDMI conversion requires an active adapter is not adopted.
The passive DP2HD4KADAP sheet lists 3840 x 2160 at 30 Hz and no HDR support. C044C
Exact-model counterexample to a universal active-for-4K rule. No claim that all passive adapters or all DP++ sources support this mode.
128-HDMI-DISPLAYPORT lists 3840 x 2160 at 60 Hz; its notes require both source and display to support that resolution and refresh rate. C045C
Exact-model stated mode, not independent measured performance, unrestricted HDR/color-mode support or a guarantee for a chain of converters.
Can another adapter fix a direction mismatch?
An extra physical coupler does not document a missing conversion path. Prefer the exact supported source-to-display path and establish each powered or converting stage separately. This comparison does not approve an arbitrary chain.
Evidence and exact scope
An active DisplayPort-to-HDMI converter translates a DisplayPort source for an HDMI display; direction is product-specific. C043A
Consumer identification / documented standard or product class only
128-HDMI-DISPLAYPORT is explicitly one-way from an HDMI source to a DisplayPort display. Its attached USB-A lead is described for power, and the power table specifies 5 V DC. C045B
Exact 128-HDMI-DISPLAYPORT. USB connector-type metadata does not establish a USB video-data transport; no generic power demand or charging function inferred.
A REFERENCE TO KEEP
Direction, requirements and source limits.
Letter PDF (legacy download held for current evidence review). Current focused printable references · A4 PDF (legacy download held for current evidence review). Current focused printable references
Three pages in each edition. No product photographs, exact mechanical drawings, certification marks or wiring instructions.