All stock codes associated to this product
TS251D2G, TS-251D-2G, QN17579A, BAQNTS251D2G, BAQN-TS-251D-2G, 4713213516669
QNAP TS-251D Intel Celeron J4005 dual-core 2.0 GHz processor (burst 
up to 2.7 GHz) with 4GB RAM (1 x 4GB)
 
Overview
The TS-251D integrates secure data storage and multimedia entertainment into 
one device. Featuring a PCIe slot, the TS-251D allows you to flexibly extend NAS 
functionality and potential applications. You can enhance overall system 
performance by installing a QNAP QM2 card for M.2 SSD caching/10GbE connectivity 
combined with Qtier auto-tiering storage and installing a 10GbE/5GbE/2.5GbE 
network expansion card. In addition, TS-251D can be used with QNAPs smart AI 
photo management application, QuMagie, which integrates AI image recognition to 
group similar photos together in album People, Things and Places. The TS-251D 
features an HDMI slot to stream multimedia throughout your home. The TS-251D 
supports dual-channel hardware decoding and transcoding, allowing you to view 
NAS media files smoothly across various devices.

The PCIe port supports the installation of a 10GbE/5GbE/2.5GbE/ network 
expansion card, a QM2 card, a USB 3.1 Gen 2 (10Gbps) card, or a wireless network 
card.

Provide 4K media playback and online transcoding, while enabling cross-device 
multimedia viewing via HDMI output or streaming applications.

Snapshots fully record the system status and data. If files are accidentally 
deleted or modified, you can quickly restore previously-recorded data.

QNAP provides a wide range of multimedia applications. You can manage all 
apps through the Multimedia Console to simplify management.

HBS backs up and synchronizes NAS data to other remote servers or cloud 
storage, while QuDedup deduplicates data at the source to reduce network 
bandwidth and storage space.

Use VJBOD (Virtual JBOD) to expand your storage capacity by using the unused 
storage of other QNAP NAS. Connect up to two TR series USB storage 
enclosure.
Intel Celeron J4005 Dual-Core Processor and AES-NI Hardware 
Encryption
Powered by Intel Celeron J4005 dual-core 2.0 GHz processor (burst up to 2.7 
GHz), DDR4 RAM (up to 8 GB), one Gigabit LAN port, and supports SATA 6Gb/s hard 
drives, the TS-251D combines network expansion cards to create dependable 
read/write performance. The TS-251D features Intel AES-NI 256 
hardware-accelerated encryption for both full NAS volumes and shared folders, 
boosting system performance while securing sensitive data stored in the 
TS-251D.
Smart AI Photo Management
QuMagie integrates QuMagie Core AI image recognition technology for facial 
recognition, subject identification, and geotagging photos. Similar photos are 
categorized into People, Places, and Things albums. Moreover, QuMagie features a 
built-in timeline scroll, customizable folder covers, iOS Live Photo display and 
a powerful search tool, to provide you with the ultimate photo management and 
image sharing solution.
Real-Time 4K Video Transcoding
Featuring advanced Intel UHD Graphics, the TS-251D supports dual-channel 4K 
hardware decoding and real-time transcoding, allowing you to convert videos to 
universal file formats that can be smoothly played across various devices*. You 
can also watch high-quality 4K media files on an HDTV using the HDMI output or 
with Plex Media Server to stream media files to mobile devices and media 
streaming devices (including DLNA, Roku, Apple TV, Amazon Fire TV and 
Chromecast). The QNAP RM-IR004 remote control (sold separately) can be 
configured using QButton to customize individual button actions, providing a 
more user-friendly NAS experience.
Multiple Ways To Enjoy Your Multimedia
QNAP provides a wide range of multimedia applications for you to easily enjoy 
photos, music, and videos.

Multimedia Console consolidates all QTS multimedia applications into one app 
for easier and centralized multimedia app management.

Cinema28 enables single-interface management of all media files and can 
stream files to every connected device throughout your home.

Qmedia allows music, photos and videos to be effortlessly streamed to Android 
TV, Apple TV, and Amazon Fire TV or set-top boxes.
Easy and Secure File Management
File Station centralizes files stored on your TS-251D and in the cloud. You 
can easily upload files from your computer, drag and drop files between folders, 
rename files, delete files, and configure file and folder permissions to prevent 
unauthorized access. Moreover, with Microsoft Office Online you can open and 
modify Microsoft Office documents stored on the TS-251D, without having to 
download Word documents, Excel worksheets, and PowerPoint presentations from 
your NAS to the PC. When it comes to sharing sensitive or confidential files on 
the TS-251D, you can use File Station to enhance data security effectively by 
encrypting files into a .qenc file, set a password, and then have file 
recipients use QENC Decrypter to decrypt the sent file.
Multi-Point File Backup, Access, and Sync
The TS-251D stores data and files centrally, and supports file sharing 
protocols, including SMB/CIFS, AFP and NFS for Windows, Mac, and Linux/UNIX 
devices. Coupled with Qsync (a utility that transforms a QNAP NAS into a secure, 
high-capacity data center for file synchronization) any file uploaded to the 
TS-251D becomes available for all linked devices, such as computers, laptops, 
and mobile devices. Hybrid Backup Sync helps you easily backup or synchronize 
data on the TS-251D to another QNAP NAS, remote servers, or cloud storage for 
disaster recovery. Additionally, QuDedup technology greatly improves the 
efficiency of multi-version backup to the destination storage, while optimizing 
storage utilization. You can install the QuDedup Extract Tool on your computer 
and restore deduplicated files to their normal status.
Protect Important Data With Snapshots
Snapshots help protect your data by fully recording the NAS system state and 
metadata. You can use snapshots to quickly restore files to a 
previously-recorded state when files are accidentally deleted or modified, or 
when the system is compromised by ransomware. QNAP snapshots are block-based and 
only record modified data. Not only does this save storage space, but also 
reduces the time required to back up and restore data.
Extend NAS Functionality With The PCIe Slot
With a PCIe expansion Gen 2.0 x 4 slot, the TS-251D provides flexibility in 
extending NAS functionality and potential applications. To optimize system 
performance, install a QNAP QM2 card for M.2 SSD caching/10GbE connectivity and 
use with Qtier tiered storage for optimal system performance. You can also use 
the TS-251D as a wireless access point by installing a compatible QNAP 
QWA-AC2600 wireless network card to create a wireless media streaming 
environment. Moreover, by configuring the QXG-10GbE/5GbE network expansion 
cards, you can upgrade your network to high-speed connectivity with an existing 
CAT 5e cable. Alternatively, you can add an affordable QNAP QNA-UC5G1T USB 3.0 
to 5GbE adapter to your TS-251D and laptop to enjoy higher network speeds, or 
boost the USB connectivity of the TS-251D by installing a USB 3.1 Gen 2 (10Gbps) 
card.
QVR Pro Safeguards Your Environment
QNAPs QVR Pro surveillance solution allows you to arrange dedicated, 
independent storage space for surveillance data on the TS-251D and leverages 
scalable storage advantages. With QVR Pro, camera management, storage space 
allocation, camera live view, and playback is greatly simplified. You can also 
use USB webcams as network cameras with the QUSBCam2 app, and remotely monitor 
surveillance feeds anytime with QVR Pro Client mobile app.
Multiply Your Productivity
The app-driven QTS operating system provides solutions for simplifying file 
backup, management, search, and more.

QmailAgent
Centrally manage and switch between different email accounts, back up emails 
to the NAS, and safeguard email security and personal privacy.

Notes Station 3
Notes Station 3 can bring the advantages of collaborative note-taking with 
improved productivity to provide higher efficiency for your workgroup.

Smart Filing
Qfiling automates file organization. Files are automatically archived into 
folders based on your settings.

Full-Text Search
Qsirch quickly finds images, music, videos, documents, emails, and other 
files.
Flexible and Economical Storage Expansion
QNAP provides an easy and flexible solution for increasing storage capacity 
before you run out of storage space. Here are the following ways you can expand 
NAS storage for accommodating data and business growth:

Upgrade RAID Capacity
Hot-swap lower-capacity drives with larger-capacity drives for your QNAP NAS 
to grow with your business.

VJBOD
Use Virtual JBOD (VJBOD) to expand storage capacity by using unused storage 
in other QNAP NAS. Up to 8 QNAP NAS can be mounted as local disks on the 
TS-251D.

Attach Expansion Enclosures
Easily expand NAS capacity by connecting two TR-002, TR-004 USB hardware RAID 
external enclosures with QNAPs Storage & Snapshots Manager 
application.
Specifications
  
  
    | CPU | Intel Celeron J4005 
      dual-core 2.0 GHz processor (burst up to 2.7 GHz) | 
  
    | CPU 
      Architecture | 64-bit 
      x86 | 
  
    | Graphic 
      Processors | Intel HD Graphics 
      600 | 
  
    | Floating Point 
      Unit | Yes | 
  
    | Encryption 
      Engine |  (AES-NI) | 
  
    | Hardware-accelerated 
      Transcoding | Yes | 
  
    | System 
      Memory | 2 GB SO-DIMM DDR4 (1 x 
      2 GB) | 
  
    | Maximum 
      Memory | 8 GB (2 x 
      4GB) | 
  
    | Memory 
      Slot | 2 x SO-DIMM DDR4 
       | 
  
    | For dual-DIMM 
      configuration, you must use a pair of identical DDR4 
      modules. | 
  
    | Flash 
      Memory | 4GB (Dual boot OS 
      protection) | 
  
    | Drive 
      Bay | 2 x 3.5-inch SATA 
      6Gb/s, 3Gb/s  | 
  
    | The system is shipped 
      without HDD. | 
  
    | For the HDD 
      compatibility list, please 
      visit https://www.qnap.com/compatibility/ | 
  
    | Drive 
      Compatibility | 3.5-inch SATA hard disk 
      drives | 
  
    | 2.5-inch SATA hard disk 
      drives | 
  
    | 2.5-inch SATA solid 
      state drives | 
  
    | Hot-swappable | Yes | 
  
    | M.2 SSD 
      Slot | Optional via a QM2 PCIe 
      adapter | 
  
    | SSD Cache 
      Acceleration Support | Yes | 
  
    | Gigabit Ethernet 
      Port (RJ45) | 1  | 
  
    | Expandable with an 
      optional PCIe adapter | 
  
    | 5 Gigabit Ethernet 
      Port | Expandable with an 
      optional PCIe adapter | 
  
    | 10 Gigabit Ethernet 
      Port | Expandable with an 
      optional PCIe adapter | 
  
    | Jumbo 
      Frame | Yes | 
  
    | PCIe 
      Slot | 1 | 
  
    | Slot 1: PCIe Gen 2 x4 
       | 
  
    | PCIe bandwidth 
      limitations will restrict the NAS 10GbE performance. | 
  
    | USB 2.0 
      port | 3 | 
  
    | USB 3.0 
      port | 2 | 
  
    | USB 3.1 Gen 2 
      (10Gbps) Port | Optional via a PCIe 
      expansion card | 
  
    | IR 
      Sensor |  (Optional QNAP 
      RM-IR004 remote control) | 
  
    | HDMI 
      Output | 1, HDMI 
      2.0 | 
  
    | Form 
      Factor | Tower | 
  
    | LED 
      Indicators | Power/Status, LAN, USB, 
      HDD1-2 | 
  
    | Buttons | Power, USB copy, 
      Reset | 
  
    | Dimensions 
      (HxWxD) | 168 105 226 
      mm | 
  
    | Weight 
      (Net) | 1.48 
    kg | 
  
    | Weight 
      (Gross) | 2.58 
    kg | 
  
    | Operating 
      temperature | 0 - 40 C (32F - 
      104F) | 
  
    | Relative 
      Humidity | 5-95% RH 
      non-condensing, wet bulb: 27C (80.6F) | 
  
    | Power Supply 
      Unit | External Power Adapter, 
      65W, 100-240V | 
  
    | Power Consumption: 
      HDD Sleep Mode | 8.08 
  W | 
  
    | Power Consumption: 
      Operating Mode, Typical | 15.25 
    W | 
  
    | Fan | 1 x 
    70mm | 
  
    | Sound 
      Level | 16.7 
      db(A) | 
  
    | System 
      Warning | Buzzer | 
  
    | Kensington Security 
      Slot | Yes |