Recommended Free Tools
A message handling system (MHS) is a standards-defined set of cooperating components and services that lets users exchange messages using store-and-forward delivery. In the ISO/IEC 10021 and ITU-T X.400 standards context, a Message Transfer System conveys a message from its originator to one or more recipients; user agents support preparing and viewing messages.
What does “message handling system” mean?
MHS is the formal term used in the ISO/IEC 10021 and ITU-T X.400 standards family. Its core purpose is to let users exchange messages on a store-and-forward basis: a message can be accepted for transfer and conveyed onward rather than requiring the sender and recipient to communicate at the same moment. ITU-T X.420 describes this purpose for interpersonal messaging.
As an Amazon Associate I earn from qualifying purchases.
The term here refers to the standards-defined architecture, not automatically to every modern application or product described generically as a message-handling system. The cited standards do not establish that such products implement X.400.
The Tool Desk
Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →How does an MHS work?
- Preparation and submission: A user works through a user agent to prepare and submit a message.
- Transfer: The Message Transfer System (MTS) conveys the message. Message transfer agents cooperate to perform the store-and-forward transfer function.
- Delivery: The message reaches one or more recipients’ agents. An optional message store can support storage, and access units can connect the MTS with other kinds of communication systems.
User agents and transfer agents have different roles: user agents support user-facing functions such as preparing, storing, and displaying messages, while transfer agents perform message transfer within the MTS.
#1 Best Overall
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
- Convert USB-A Ports to USB-C: Designed to connect USB-C earphones, cables, flash drives, card readers, and other USB-C accessories to standard USB-A ports. Plug-and-play with no drivers or software required.
- Aluminum Alloy Housing: Built with a sturdy aluminum alloy shell that aids in heat dissipation and protects against daily wear and scratches. Designed to maintain a stable and secure connection.
- Compact & Travel-Friendly: The ultra-compact design allows the adapter to stay plugged into your device without blocking adjacent ports or adding bulk, reducing wear and tear on your original USB ports.
- 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.
Is an MHS the same as email?
Not exactly. Interpersonal messaging—including email-like exchange between users—is one service covered by the MHS standards family, but the family is broader than interpersonal email. ITU-T F.400/X.400 also identifies related specifications for electronic data interchange (EDI), voice messaging, message stores, and routing. The shared MHS idea is organized message exchange; the service and component details vary.
| Area | What it covers | Relevant standard or recommendation |
|---|---|---|
| Interpersonal messaging | Exchange of messages between users on a store-and-forward basis | ITU-T X.420 (1999) |
| Voice messaging | OSI MHS protocol for store-and-forward exchange of voice-encoded messages | ITU-T X.440 (June 1999) |
| EDI messaging | System and service for electronic data interchange messaging | ISO/IEC 10021-8:1999 |
| Message store | Support for retrieving messages and submitting them through the store | ITU-T X.413 |
Which standards define the MHS architecture?
The ISO/IEC 10021 and ITU-T X.400/F.400 standards family provides the formal context. The two ISO editions below are identified by ISO as published and confirmed; their publication dates are included because these are older editions.
Rank #2
- 5-in-1 USB-C Hub: Experience comprehensive connectivity featuring a Power Delivery input, two USB-A 2.0 ports, a USB-A 3.0 port, and an HDMI port. (Note: The USB-C power delivery input port is only for connecting an external wall charger to power your laptop and cannot power peripheral devices.)
- 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
- Quick Data Transfers: Accelerate your productivity with rapid data transfers using a high-speed 5Gbps USB 3.0 port and two 480Mbps USB 2.0 ports.
- 4K HDMI Display: Enhance your visual experience with a hub capable of delivering 4K resolution at 30Hz in both mirror and extend modes. Please note that this hub is compatible with MacBook (macOS 12 and newer), Windows 10 and 11, ChromeOS, and laptops equipped with DP Alt Mode and Power Delivery. Note: This device is not compatible with Linux.
- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
| Document | Role | Edition status and publication date |
|---|---|---|
| ISO/IEC 10021-1:2003 | System and service overview | Published and confirmed; November 2003 |
| ISO/IEC 10021-2:2003 | Overall architecture, including abstract models, configuration, naming and addressing, routing, and directory use | Published and confirmed; December 2003 |
Other relevant documents include ITU-T F.400/X.400 (June 1999), which presents the MHS system and services and lists related recommendations, as well as the service-specific standards in the table above.
What to check when someone uses the term today
Because “message handling system” can be used outside its formal standards meaning, establish the context before assuming a particular architecture. If a document or product claims standards alignment, look for an explicit reference to ISO/IEC 10021 or ITU-T X.400 and identify the edition. Otherwise, treat the phrase as a generic description until its components, protocols, and intended service are specified.
Quick Recap
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
Rank #4
- Dual Converters, Infinite Potential：Includes 2× USB C male to USB A female adapters and 2× USB A male to USB C female adapters. Perfect for a wide range of uses—tablets with Bluetooth keyboards, expand USB ports on macbook, and more. Two different converters for all your daily needs
- Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
- Upgraded Exquisite Craftsmanship: With an aluminum alloy housing and metal connector, the usbc to usb adapter is extremely durable and sturdy. Rigorously tested to withstand more than 10,000 times of plugging and unplugging, ensuring long-lasting performance
- Broad Compatible: The usb c to usb adapter widely supports all USB C/ USB A devices like laptops, tablets, cellphones, car chargers, and phone chargers. Such as compatible with MacBook Pro/Air 2023/2022, Thunderbolt 4/3 Devices,Apple MagSafe Watch 9/8/7/SE/Ultra, iPad Pro 2022/2021, Samsung Galaxy S23/S20/S10, and iPhone 17/16/15 Pro. Plug and play
- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
Rank #3
- Sleek 7-in-1 USB-C Hub: Features an HDMI port, two USB-A 3.0 ports, and a USB-C data port, each providing 5Gbps transfer speeds. It also includes a USB-C PD input port for charging up to 100W and dual SD and TF card slots, all in a compact design.
- Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
- Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
- Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
