Notes on Specific Monitors

The following list describes some monitors that have been tested. It highlights the variability in DDC implementation among monitors.

Apple Cinema Display A1082

Has both I2C and USB interfaces.

VCP Version: 2.0
Controller Manufacturer: unspecified
Controller Model: unspecified
Firmware version: unspecified
Manufacture year: 2005

I2C interface has more VCP features than USB interface.

USB interface does not report VCP version (feature DF).

Able to read EDID over USB.

Capabilities string does not begin and end with parentheses.

Asus VE247

VCP version: 2.0
Controller Manufacturer: RealTek
Controller Model: mh=0x00, ml=0x24, sh=0x82
Firmware version: 2.0
Maufacture year: 2010

Responds to unknown VCP codes using the DDC NULL message instead of setting the Unsupported VCP code bit in the GETVCP response.

Sensible reponses to VCP codes 0B and 0C.

Dell P2411

VCP version: 2.1
Controller Manufacturer: Mstar
Controller Model: mh=0x00, ml=0x00, sh=0x56
Firmware version: 1.1
Manufacture year: 2011

Lots of I2C errors. Heavily dependant on retries. The CAPABILITIES command sometimes fails, even with maximum retries. More recently, all I2C responses contain errors.

Reports VCP code 0B (color temperature increment) as 1 degree Kelvin, which makes the GETVCP response to VCP code 0C (color temperature request) nonsensical.

Dell Ultrasharp 1905FP

Does not support DDC.

Dell U3011

VCP version: 2.1
Controller manufacturer: Mstar
Controller Model: mh=0x00, ml=0x94, sh=0x85
Firmware version: 1.5
Manufacture year: 2012

If a value is set using SETVCP, the new value takes effect and appears in the on-screen display. However, GETVCP sometimes still retieves the old value, not the new one.

Reports VCP code 0B (color temperature increment) as 1 degree Kelvin, which makes the GETVCP response to VCP code 0C (color temperature request) nonsensical.

Eizo Coloredge CG19

VCP version: unreported
Controller manufacturer and model: unreported (VCP feature code C8 unsupported)
Firmware version: unreported (VCP feature code C9 unsupported)

Reports EDID at I2C bus address 0x50. Does not support DDC over I2C (bus address 0x37).

Does implement MCCS over USB, and appears to conform to the USB Monitor Control Class Specification. However, it appears that the more sophisticated monitor features such as LUT loading use manufacturer specific USB HID reports.

Unable to read EDID over USB, even though the HID Report for EDID can be located.

To set color related VCP feature values, Custom Color mode must be selected. If set to sRGB or Calibrated, the SETVCP command will appear to succeed, but will have no effect. (In sRGB mode, Brightness can be set, in Calibrated mode it cannot.)

Gateway Diamondtron VX920

VCP version: Unspecified, implies 1.0
Controller manufacturer and model: Unknown (VCP feature code C8 unsupported)
Firmware version: Unknown (VCP feature code C9 unsupported)

Hanns G Hi221D

VCP version: 2.1
Controller manufacturer: Mstar
Controller model: mh=0x00, ml=0x92, sh=0x00
Firmware version: 0.6

All GETVCP requests return a value, whether or not the feature is valid for the monitor. The monitor never reports a feature as unsupported.

HP LP2480zx

VCP version: 2.1
Controller manufacturer: Genesis
Controller Model: mh=0xff, ml=0xff, sh=0x80
Firmware version: 0.139
Manufacture year: 2008

Heavily reliant on manufacturer specific VCP codes. Most color related features, including loading the internal LUT, are not supported using standard VCP feature codes.

Implements MCCS over USB as well as I2C. However, the USB implementation appears to be non-standard. It does not conform to the USB Monitor Control Class Specification.

Sensible reponses to VCP codes 0B and 0C.

Capabilities string does not match actual capabilities observed. For example, capaibilites does not include VCP feature code 0x10, brightness, which is recognized by getvcp and setvcp.

Capabilities string does include cmds() segment listed supported commands, ore model() segment listing model.

HP w2207

VCP Version: 2.1
Controller manufacturer: Mstar
Firmware Version: 3.5
Manufacture year: 2007

Color temperature increment (feature x0B) and request (feature x0C) result in a color temperature of 13,000 degress Kelvin

Responds with data to all VCP feature requests, never reports a feature as unsupported

HP ZR2740w

VCP version: 2.2

Implements only a few VCP codes.

VCP feature codes 0B and 0C unsupported.

Iilyama PL2779Q

VCP Version: 2.1
Controller manufacturer: unknown (feature code xC8 unsupported)
Firmware version: unkown (feature code xC9 unsupported)
Manufacture year: 2013

Color temperature increment (feature x0B) and request (feature x0C) result in a color temperature of 26,100 degress Kelvin

Does not include command x02 (VCP Response) or xE3 (Capabilities Reply) in its capabilities string, even though these are supported.

Responds to several VCP feature not listed in capabilities

LG Ultrawide

VCP version: 2.1
Controller manufacturer and model: STK
Firmware version: 0.1
Manufacture year: 2014

Feature codes are not separated by blanks in the vcp() section of the capabilities string.

No serial number in the EDID.

When responding to a Get VCP Feature request, the monitor never sets sets the Result Code field of the VCP Feature Reply to Unsupported VCP Code. Instead, it always reports No Error.
For unsupported VCP codes, all bytes in the response (MH, ML, SH, SL) are set to 0x00.

NEC LCD3090WQXi

VCP Version 2.0
Controller manufacturer and model: unreported (VCP feature code C8 unsupported)
Firmware version: unreported (VCP feature code C9 unsupported)

NEC PA241

VCP Version 2.0
Controller manufacturer and model: unreported (VCP feature code C8 unsupported)
Firmware version: unreported (VCP feature code C9 unsupported)

Implements both I2C and USB interfaces.

Makes heavy use of manufacturer specific VCP feature codes. Also, ddcutil capabilities --verbose reports numerous manufacturer specific DDC commands The USB interface also makes heavy use of manufacturer specific usage codes.

Monitor must be set to ??? to allow changes.

VCP code 0x0c (Color Temperature Request) returns 0, which is nonsensical.

Does not use the usual VCP codes (.e.g. 0x16/Red Gain) for color control. Instead uses the 6 axis color control features 0x8c..0xa0.

Samsung Syncmaster 213T

Does not support DDC.

Samsung Syncmaster 730B

VCP version: Unspecified, implies 1.0
Controller manufacturer and model: Unknown (VCP feature code C8 unsupported)
Firmware version: Unknown (VCP feature code C9 unsupported)

The capabilities string spcifies the values for non-continuous features in decimal rather than hexadecimal

VCP feature codes 0B and 0C unsupported.