Dell D2421H User manual

Monitor Model: D2421H/D2721H/D2421DS
Regulatory Model: D2421Ho/D2721Ho/D2421DSo
Dell Monitor
D2421H/D2721H/D2421DS
User’s Guide

Copyright © 2020 Dell Inc. or its subsidiaries. All rights reserved. Dell, EMC, and other
trademarks are trademarks of Dell Inc. or its subsidiaries. Other trademarks may be trademarks of their
respective owners.
2020 – 04
Rev. A00
NOTE: A NOTE indicates important information that helps you make
better use of your computer.
CAUTION: A CAUTION indicates potential damage to hardware or loss
of data if instructions are not followed.
WARNING: A WARNING indicates a potential for property damage,
personal injury, or death.

│3
Contents
About Your Monitor .................................5
Package Contents . . . . . . . . . . . . . . . . . . . . . . 5
Product Features. . . . . . . . . . . . . . . . . . . . . . .6
Identifying Parts and Controls. . . . . . . . . . . . . . . .7
Monitor Specifications. . . . . . . . . . . . . . . . . . . 11
Plug and Play. . . . . . . . . . . . . . . . . . . . . . . . 23
LCD Monitor Quality & Pixel Policy . . . . . . . . . . . . 23
Setting Up the Monitor .............................24
Connecting the stand . . . . . . . . . . . . . . . . . . . 24
Using the Tilt and Vertical Extension . . . . . . . . . . . 26
Rotating the Monitor. . . . . . . . . . . . . . . . . . . . 27
Connecting Your Monitor . . . . . . . . . . . . . . . . . 28
Removing the Monitor Stand . . . . . . . . . . . . . . . 29
Wall Mounting (Optional) . . . . . . . . . . . . . . . . . 31
Operating the Monitor ..............................32
Power On the Monitor . . . . . . . . . . . . . . . . . . . 32
Using the Front-Panel Controls . . . . . . . . . . . . . . 32
Using the OSD Lock function . . . . . . . . . . . . . . . 33
Using the On-Screen Display (OSD) Menu . . . . . . . . 33
Troubleshooting ...................................41
Common Problems . . . . . . . . . . . . . . . . . . . . . 41

4 │
Product-Specific Problems . . . . . . . . . . . . . . . . 44
Appendix.........................................45
Safety Instructions. . . . . . . . . . . . . . . . . . . . . 45
Contact Dell . . . . . . . . . . . . . . . . . . . . . . . . 45
Setting Up Your Monitor . . . . . . . . . . . . . . . . . . 45
Setting Up Your Monitor . . . . . . . . . . . . . . . . . . 47
Maintenance Guidelines . . . . . . . . . . . . . . . . . . 49

About Your Monitor │5
About Your Monitor
Package Contents
Your monitor ships with all the components shown below. Ensure that you have received
all the components and Contact Dell if anything is missing.
NOTE: Some items may be optional and may not ship with your monitor. Some
features or media may not be available in certain countries.
Display
a. D2421DS
b. D2421H/D2721H
Stand Riser
a. D2421DS
b. D2421H
c. D2721H
Stand base
a. D2421DS
b. D2421H
c. D2721H
Screws x 2 (D2721H)
Power Cable
HDMI Cable
a
a
b
b c
b c
a

6 │About Your Monitor
Quick Setup Guide
Safety and Regulatory
Information
Product Features
The Dell D2421H/D2721H/D2421DS flat-panel display has an active matrix, Thin-Film
Transistor (TFT), Liquid Crystal Display (LCD) Panel with LED backlight. The monitor
features include:
• D2421H: 60.5 cm (23.8 in.) diagonal viewable image size, 1920 x 1080 resolution,
plus full-screen support for lower resolutions.
• D2721H: 68.6 cm (27 in.) diagonal viewable image size, 1920 x 1080 resolution, plus
full-screen support for lower resolutions.
• D2421DS: 60.5 cm (23.8 in.) diagonal viewable image size, 2560 x 1440 resolution,
full-screen support for lower resolutions.
• Tilt adjustment capability.
• Removable pedestal and Video Electronics Standards Association (VESA) 100 mm
mounting holes for flexible mounting solutions.
• D2421H/D2721H:Digital connectivity with HDMI and Analog connectivity with
VGA.
• D2421DS: Digital connectivity with DisplayPort and HDMI.
• Height adjustment and pivot capability for D2421DS.
• Plug and play capability if supported by your system.
• On-Screen Display (OSD) adjustments for ease of set-up and screen optimization.
• Security lock slot.
• RoHS compliant.
• Possible long-term effects of blue light emission from the monitor may cause
damage to the eyes, including eye fatigue, digital eye strain, and so on. TÜV-
certified ComfortView feature is designed to reduce the amount of blue light
emitted from the monitor to help optimize eye comfort.
• Arsenic-free glass and Mercury-free for the panel only.
• 0.5 W standby power when in the sleep mode.

About Your Monitor │7
Identifying Parts and Controls
NOTE: The graphics are used for the purpose of illustration only. Appearance on
the computer may vary.
D2421H
Front view
123
Label Description
1Function buttons (For more information, see Operating the Monitor)
2Power On/Off button
3 LED indicator
Back view
⏨Წᱴ⽰ಞ/FlatPanel Monitor
ශModelNo.: D2421H
䗉ޛ⭫Ⓠ/Rating:
100-240V~50/60Hz 0.8A
࡬䙖൦ѣളMade in China
࡬䙖ᰛᵕManufactureddate:
DELL D2421H
April2020




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
⏨Წᱴ⽰ಞ/FlatPanel Monitor
ශModelNo.: D2421H
䗉ޛ⭫Ⓠ/Rating:
100-240V~50/60Hz 0.8A
࡬䙖൦ѣളMade in China
࡬䙖ᰛᵕManufactureddate:
DELLD2421H
April2020






1
4
2
3
Back View with Monitor Stand
Label Description Use
1 VESA mounting holes (100 mm) Supports optional mounting of the monitor
using a VESA mount or arm.
2 Security lock slot Secures monitor with security lock
(security lock not included).

8 │About Your Monitor
3 Regulatory rating label with
Barcode serial number
Lists the regulatory approvals. Refer to
this label if you need to contact Dell for
technical support.
4 Stand release button Release stand from monitor.
Bottom View
1 2 3 4
Label Description Use
1 AC power connector To connect the monitor power cable.
2 HDMI connector To connect your computer to the monitor using a HDMI
cable.
3 VGA connector To connect your computer to the monitor using a VGA
cable.
4 Earphone connector To connect your earphone
D2721H
Front view
123
Label Description
1Function buttons (For more information, see Operating the Monitor)

About Your Monitor │9
2Power On/Off button
3 LED indicator
Back view
1
2
3
4
⏨Წᱴ⽰ಞ/FlatPanel Monitor
ශModelNo.: D2721H
䗉ޛ⭫Ⓠ/Rating:
100-240V~50/60Hz 1.0A
࡬䙖൦ѣളMadein China
࡬䙖ᰛᵕManufactureddate:
DELL D2721H
April2020






⏨Წᱴ⽰ಞ/FlatPanel Monitor
ශModelNo.: D2721H
䗉ޛ⭫Ⓠ/Rating:
100-240V~50/60Hz 1.0A
࡬䙖൦ѣളMadein China
࡬䙖ᰛᵕManufactureddate:
DELL D2721H
April2020






Back View with Monitor Stand
Label Description Use
1 VESA mounting holes (100 mm) Supports optional mounting of the monitor
using a VESA mount or arm.
2 Security lock slot Secures monitor with security lock
(security lock not included).
3 Regulatory rating label with
Barcode serial number
Lists the regulatory approvals. Refer to
this label if you need to contact Dell for
technical support.
4 Stand release button Release stand from monitor.
Bottom View
123
Label Description Use
1 AC power connector To connect the monitor power cable.

10 │About Your Monitor
2 HDMI connector To connect your computer to the monitor using a HDMI
cable.
3 VGA connector To connect your computer to the monitor using a VGA
cable.
D2421DS
Front view
123
Label Description
1Function buttons (For more information, see Operating the Monitor)
2Power On/Off button
3 LED indicator
Back view
1
2
3
Back View with Monitor Stand

About Your Monitor │11
Label Description Use
1 VESA mounting holes (100 mm) Supports optional mounting of the monitor
using a VESA mount or arm.
2 Security lock slot Secures monitor with security lock
(security lock not included).
3 Regulatory rating label with
Barcode serial number
Lists the regulatory approvals. Refer to
this label if you need to contact Dell for
technical support.
Bottom View
123
Label Description Use
1 AC power connector To connect the monitor power cable.
2 HDMI connector To connect your computer to the monitor using a HDMI
cable.
3 DP connector To connect your computer to the monitor using a DP
cable.
Monitor Specifications
Flat-Panel Specifications
Model number D2421H D2721H
Screen type Active matrix - TFT LCD Active matrix - TFT LCD
Panel type In-Plane Switching
Technology
In-Plane Switching
Technology
Viewable image
Diagonal
Horizontal Active Area
Vertical Active Area
Area
604.7 mm (23.8 in.)
527.04 mm (20.76 in.)
296.46 mm (11.67 in.)
156246.27 mm² (242.27 in.²)
686.0 mm (27 in.)
597.89 mm (23.54 in.)
336.31 mm (13.24 in.)
201076.91 mm² (311.67 in.²)
Pixel pitch 0.2745 x 0.2745 mm 0.3114 x 0.3114 mm

12 │About Your Monitor
Pixel per inch (PPI) 92 81
Viewing angle
Horizontal
Vertical
178° (typical)
178° (typical)
178° (typical)
178° (typical)
Brightness 250 cd/m² (typical) 250 cd/m² (typical)
Contrast ratio 1000 to 1 (typical) 1000 to 1 (typical)
Faceplate coating Anti-glare with hard-coating
3H hardness
Anti-glare with hard-coating
3H hardness
Backlight White LED edgelight system White LED edgelight system
Response Time 5 ms (gray to gray - fast
mode)
8 ms (gray to gray - normal
mode)
5 ms (gray to gray - fast
mode)
8 ms (gray to gray - normal
mode)
Color Depth 16.7 mil colors 16.7 mil colors
Color Gamut 72% NTSC(CIE 1931)
and 83% NTSC(CIE 1976)
72% NTSC(CIE 1931)
and 83% NTSC(CIE 1976)
Connectivity 1x VGA, 1x HDMI 1.4, 1x
Earphone (φ3.5 mm)
1x VGA, 1x HDMI 1.4
Border width (edge of
monitor to active area)
6.25 mm (Side)/6.24 mm
(Top)/22.26 mm (Bottom)
6.98 mm (Side)/6.98 mm
(Top)/20.90 mm (Bottom)
Adjustability
Height adjustable stand
Tilt
Pivot
N/A
-5° to 20°
N/A
N/A
-5° to 20°
N/A
Security Security lock slot (cable lock
sold separately)
Security lock slot (cable lock
sold separately)
Model number D2421DS
Screen type Active matrix - TFT LCD
Panel type In-Plane Switching Technology
Viewable image
Diagonal
Horizontal Active Area
Vertical Active Area
Area
604.5 mm (23.8 in.)
526.85 mm (20.74 in.)
296.35 mm (11.67 in.)
156132.00 mm² (242.03 in.²)

About Your Monitor │13
Pixel pitch 0.2058 x 0.2058 mm
Pixel per inch (PPI) 123
Viewing angle
Horizontal
Vertical
178° (typical)
178° (typical)
Brightness 300 cd/m² (typical)
Contrast ratio 1000 to 1 (typical)
Faceplate coating Anti-glare with hard-coating 3H hardness
Backlight White LED edgelight system
Response Time 5 ms (gray to gray - fast mode)
8 ms (gray to gray - normal mode)
Color Depth 16.7 mil colors
Color Gamut 99% sRGB(TYP)
Connectivity 3x HDMI 1.4, 1x DP 1.2
Border width (edge of
monitor to active area)
7.08 mm (Side)/7.02 mm (Top)/19.83 mm (Bottom)
Adjustability
Height adjustable stand
Tilt
Pivot
100 mm
-3.5° to 21.5°
90° clockwise
Security Security lock slot (cable lock sold separately)
Resolution Specifications
Model number D2421H/D2721H D2421DS
Scan range
• Horizontal
• Vertical
30 kHz to 83 kHz (automatic)
50 Hz to 75 Hz (automatic)
30 kHz to 83 kHz (automatic)
50 Hz to 75 Hz (automatic)
Maximum preset
resolution
1920 x 1080 at 60 Hz 2560 x 1440 at 60 Hz

14 │About Your Monitor
Video display
capabilities
( HDMI&DP
playback)
480i, 480p, 576i, 576p, 720p,
1080i, 1080p
480i, 480p, 576i, 576p, 720p,
1080i, 1080p
Preset Display Modes
The following table lists the preset modes for which Dell guarantees image size and
centering:
D2421H/D2721H
Display Mode
Horizontal
Frequency
(kHz)
Vertical
Frequency
(Hz)
Pixel Clock
(MHz)
Sync Polarity
(Horizontal/
Vertical)
VESA, 720 x 400 31.5 70.1 28.3 -/+
VESA, 640 x 480 31.5 59.9 25.2 -/-
VESA, 640 x 480 37.5 75.0 31.5 -/-
VESA, 800 x 600 37.9 60.3 40.0 +/+
VESA, 800 x 600 46.9 75.0 49.5 +/+
VESA, 1024 x 768 48.4 60.0 65.0 -/-
VESA, 1024 x 768 60.0 75.0 78.8 +/+
VESA, 1152 x 864 67.5 75.0 108.0 +/+
VESA, 1280 x 1024 64.0 60.0 108.0 +/+
VESA, 1280 x 1024 80.0 75.0 135.0 +/+
VESA, 1600 x 900 60.0 60.0 108.0 +/+
VESA, 1920 x 1080 67.5 60.0 148.5 +/+
D2421DS
Display Mode
Horizontal
Frequency
(kHz)
Vertical
Frequency
(Hz)
Pixel Clock
(MHz)
Sync Polarity
(Horizontal/
Vertical)
VESA, 720 x 400 31.5 70.1 28.3 -/+
VESA, 640 x 480 31.5 59.9 25.2 -/-
VESA, 640 x 480 37.5 75.0 31.5 -/-

About Your Monitor │15
VESA, 800 x 600 37.9 60.3 40.0 +/+
VESA, 800 x 600 46.9 75.0 49.5 +/+
VESA, 1024 x 768 48.4 60.0 65.0 -/-
VESA, 1024 x 768 60.0 75.0 78.8 +/+
VESA, 1152 x 864 67.5 75.0 108.0 +/+
VESA, 1280 x 1024 64.0 60.0 108.0 +/+
VESA, 1280 x 1024 80.0 75.0 135.0 +/+
VESA, 1600 x 900 60.0 60.0 108.0 +/+
VESA, 1920 x 1080 67.5 60.0 148.5 +/+
VESA, 1920 x 120074.0 60.0 154.0 +/+
VESA, 2560 x 1440 88.8 60.0 241.5 +/-
Electrical Specifications
Model number D2421H
Video input signals • Analog RGB: 0.7 V ± 5 %, 75 ohm input impedance
• HDMI 1.4 (HDCP 1.4), 150 mV=<Vp-p=<1560 mV for each
differential line, 100 ohm input impedance per differential pair
Synchronization
input signals
Separate horizontal and vertical synchronizations, polarity-free
TTL level, SOG (Composite SYNC on green)
AC input voltage /
frequency / current
100 VAC to 240 VAC / 50 Hz or 60 Hz ± 3 Hz / 0.8 A (typical)
Inrush current 120 V: 30 A (Max.)
240 V: 60 A (Max.)
Model number D2721H
Video input signals • Analog RGB: 0.7 V ± 5 %, 75 ohm input impedance
• HDMI 1.4 (HDCP 1.4), 150 mV=<Vp-p=<1560 mV for each
differential line, 100 ohm input impedance per differential pair
Synchronization
input signals
Separate horizontal and vertical synchronizations, polarity-free
TTL level, SOG (Composite SYNC on green)

16 │About Your Monitor
AC input voltage /
frequency / current
100 VAC to 240 VAC / 50 Hz or 60 Hz ± 3 Hz / 1.0 A (typical)
Inrush current 120 V: 30 A (Max.)
240 V: 60 A (Max.)
Model number D2421DS
Video input signals • HDMI 1.4 (HDCP 1.4), 150 mV=<Vp-p=<1560 mV for each
differential line, 100 ohm input impedance per differential pair
• DisplayPort 1.2 (HDCP 1.4), 120mV min.(For HBR) 50 mV min.
(For HBR2) for each differential line, 100 ohm input impedance
per differential pair
Synchronization
input signals
Separate horizontal and vertical synchronizations, polarity-free
TTL level, SOG (Composite SYNC on green)
AC input voltage /
frequency / current
100 VAC to 240 VAC / 50 Hz or 60 Hz ± 3 Hz / 0.8 A (typical)
Inrush current 120 V: 30 A (Max.)
240 V: 60 A (Max.)
Physical Characteristics
The following table lists the monitor’s physical characteristics:
Model number D2421H D2721H
Signal cable type • Analog: D-Sub, 15 pins
• Digital: HDMI, 19 pins
• Analog: D-Sub, 15 pins
• Digital: HDMI, 19 pins
Dimensions: (with stand)
Height
Width
Depth
393.7 mm (15.50 in.)
539.5 mm (21.24 in.)
176.9 mm (6.96 in.)
478.5 mm (18.84 in.)
611.8 mm (24.09 in.)
236.9 mm (9.33 in.)
Dimensions: (without stand)
Height
Width
Depth
325.3 mm (12.81 in.)
539.5 mm (21.24 in.)
40.8 mm (1.61 in.)
364.2 mm (14.34 in.)
611.8 mm (24.09 in.)
47.6 mm (1.87 in.)
Stand dimensions:
Height
Width
Depth
176.4 mm (6.94 in.)
199.9 mm (7.87 in.)
176.9 mm (6.96 in.)
186.9 mm (7.36 in.)
272.7 mm (10.74 in.)
236.9 mm (9.33 in.)

About Your Monitor │17
Weight:
Weight with packaging
Weight with stand assembly
and cables
Weight without stand
assembly (For wall mount or
VESA mount considerations
- no cables)
Weight of stand assembly
4.9 Kg (10.80 lb)
3.8 Kg (8.38 lb)
3.2 Kg (7.05 lb)
0.3 Kg (0.66 lb)
6.0 Kg (13.23 lb)
4.8 Kg (10.58 lb)
4.0 Kg (8.82 lb)
0.5 Kg (1.10 lb)
Model number D2421DS
Signal cable type • Digital: DisplayPort, 20 pins
• Digital: HDMI, 19 pins
Dimensions: (with stand)
Height (extended)
Height (compressed)
Width
Depth
505.7 mm (19.91 in.)
405.7 mm (15.97 in.)
541.0 mm (21.30 in.)
211.6 mm (8.33 in.)
Dimensions: (without stand)
Height
Width
Depth
323.2 mm (12.72 in.)
541.0 mm (21.30 in.)
44.9 mm (1.77 in.)
Stand dimensions:
Height (extended)
Height (compressed)
Width
Depth
Base
391.9 mm (15.43 in.)
347.22 mm (13.67 in.)
214.6 mm (8.45 in.)
211.6 mm (8.33 in.)
214.6 mm x 211.6 mm (8.45 in. x 8.33 in.)
Weight:
Weight with packaging
Weight with stand assembly and cables
Weight without stand assembly (For wall
mount or VESA mount considerations - no
cables)
Weight of stand assembly
7.0 Kg (15.43 lb)
5.9 Kg (13.01 lb)
3.5 Kg (7.72 lb)
2.1 Kg (4.63 lb)

18 │About Your Monitor
Environmental Characteristics
Model number D2421H/D2721H/D2421DS
Temperature
• Operating
• Non-operating
0°C to 50°C (32°F to 122°F)
Storage: -20°C to 60°C (-4°F to 140°F)
Shipping: -20°C to 60°C (-4°F to 140°F)
Humidity
• Operating
• Non-operating
20 % to 90 % (non-condensing)
Storage: 5 % to 90 % (non-condensing)
Shipping: 5 % to 90 % (non-condensing)
Altitude
• Operating
• Non-operating
5,000 m (16,404 ft) max
12,191 m (40,000 ft) max
Model number D2421H D2721H D2421DS
Thermal dissipation 75.06 BTU/hour
(maximum)
68.24 BTU/hour
(typical)
95.53 BTU/hour
(maximum)
85.3 BTU/hour
(typical)
119.42 BTU/hour
(maximum)
102.36 BTU/hour
(typical)
Compliant standards
Model number D2421H/D2721H/D2421DS
RoHS Compliant yes
BFR/PVC free Monitor (excluding external cables) no
Power Management Modes
If you have VESA’s DPM compliance display card or software installed in your PC, the
monitor automatically reduces its power consumption when not in use. This is referred
to as Power Save Mode. If the computer detects input from keyboard, mouse, or other
input devices, the monitor automatically resumes functioning. The following table shows
the power consumption and signaling of this automatic power-saving feature:
D2421H
VESA Modes Horizontal
Sync
Vertical
Sync
Video Power
Indicator
Power Consumption
Normal operation Active Active Active BLUE 22 W (maximum)**
20 W (typical)

About Your Monitor │19
Active-off mode Inactive Inactive Blank ORANGE Less than 0.5 W
Switch off - - - Off Less than 0.5W *
Power Consumption Pon 14.7 W
Total Energy Consumption (TEC) 45.7 kWh
D2721H
VESA Modes Horizontal
Sync
Vertical
Sync
Video Power
Indicator
Power Consumption
Normal operation Active Active Active BLUE 28 W (maximum)**
25 W (typical)
Active-off mode Inactive Inactive Blank ORANGE Less than 0.5 W
Switch off - - - Off Less than 0.5W *
Power Consumption Pon 16.7 W
Total Energy Consumption (TEC) 52.0 kWh
D2421DS
VESA Modes Horizontal
Sync
Vertical
Sync
Video Power
Indicator
Power Consumption
Normal operation Active Active Active BLUE 35 W (maximum)**
30 W (typical)
Active-off mode Inactive Inactive Blank ORANGE Less than 0.5 W
Switch off - - - Off Less than 0.5W *
Power Consumption Pon 16.8 W
Total Energy Consumption (TEC) 52.2 kWh
NOTE:
Pon : Power consumption of On Mode measured with reference to Energy Star test method.
TEC : Total energy consumption in kWh measured with reference to Energy Star test method.
The OSD operates only in the normal operation mode. In the active-off mode, you only
could press button into Input Source.
* Zero-power consumption in OFF mode can only be achieved by disconnecting the main
cable from the monitor.
** Maximum power consumption with max luminance and contrast.
This document is informational only and reflects laboratory performance. Your product may
perform differently, depending on the software, components and peripherals you ordered

20 │About Your Monitor
and shall have no obligation to update such information. Accordingly, the customer should
not rely upon this information in making decisions about electrical tolerances or otherwise.
No warranty as to accuracy or completeness is expressed or implied.
Activate the computer and monitor to gain access to the OSD.
Pin Assignments
VGA connector
12345
678910
11 12 13 14 15
Pin number 15-pin side of theconnected signal cable
1 Video-Red
2 Video-Green
3 Video-Blue
4 GND
5 Self-test
6 GND-R
7 GND-G
8 GND-B
9 DDC +5 V
10 GND-sync
11 GND
12 DDC data
13 H-sync
14 V-sync
15 DDC clock