# Legacy Device & Historical Reference

### 15.1 Corporate History & Patents

#### **Company Timeline**

* **1996**: Co-founded **CNS Co., Ltd.**
* **2011**: Spun off as **CNS Korea**.
* **2013**: Established **IODD Co., Ltd.**

#### **Intellectual Property**

* **Patent (2nd Password)**: "Device password setting for preventing duplication of encrypted devices." (Patent-2022-0021783). Supports 4-38 digit passwords.
* **Patent (Virtual ODD)**: "Memory device recognizable as an optical disk drive and its driving method." (No. 0993935). Valid until September 9, 2028.

***

### 15.2 📜 Legacy Device Details (2531 / 2541 / MINI)

The legacy models use different physical controls and firmware structures compared to the modern ST/MINI PRO series.

#### **Hardware Characteristics**

* **Modern Series (ST300/400, MINI PRO)**: Feature a color LCD (128x160 dots) and support **Multi-LUN** (Mount up to **3 VHDs**, **1 ODD**, and **1 Physical HDD** simultaneously for a total of 5 devices).
* **Legacy Series (2531, 2541, MINI Legacy)**: Support up to **4 Virtual Drives**, **1 ODD**, and **1 Physical HDD** simultaneously.
* **IODD 2531**: Uses a **3-way Jog Dial** (Up/Down/Click) and a side back button. Supports 2.5-inch SATA HDDs up to 9.5mm. It shares the same architecture as the **ZM-VE300**. **Material**: Aluminum and PC (Plastic).
  * **Tip**: If installing a thinner **7mm** drive in a 2531, a spacer is required for a secure fit.
* **IODD 2541**: Uses **12 Touch Keys**. Based on the **ZM-VE400** architecture but with improved hardware.
* **IODD MINI (Legacy)**: Uses **12 Tactile buttons** and a Micro-B USB 3.0 connector. Uses M.2 SATA **2242** (42mm) SSDs.
* **Tip**: For older 2541 units with touch sensitivity issues, placing a thin sheet of plastic or paper between the HDD and the front body (not the cover) can improve responsiveness.

#### **Additional Modern Features (ST/MINI PRO)**

* **Bitmap File Viewer (Experimental)**: Supports viewing small bitmap images (under 128x160 resolution, **1/16/24-bit** color depth).
* **Text Viewer**: Supports reading `.txt` files in UTF-16 (UCS-2 LE) and ASCII formats.
* **Standalone Mode**: Allows users to configure settings or browse files using a USB power bank without connecting to a PC (Hold key **\[5]** or **\[M]** during connection).
* **Admin/User Login**: When encryption is active, the first digit of the password entry identifies the user: **`0`** for Administrator, **`1`** through **`4`** for standard users. (e.g., if the admin password is `1234`, enter `01234`).

#### **Legacy-Specific Features (2531 / 2541)**

* **Force USB 3.0**: A menu option to force the device to maintain a USB 3.0 connection even in harsh conditions where it might otherwise downshift to USB 2.0.
* **Instant Save**: Quickly saves the current configuration and loading state.
* **Fixed/Removable filenames**: Use `.VHD` for fixed disks and `.RMD` for removable media (Legacy only).

#### **Emergency Recovery Procedures**

| Device Type       | Procedure          | Description                                                                           |
| ----------------- | ------------------ | ------------------------------------------------------------------------------------- |
| **ST / MINI PRO** | **Force Recovery** | Hold **\[9] + \[Enter]** for 7 seconds while connecting. Re-flashes current firmware. |
| **2541 / 2531**   | **Tact Switch**    | Open back cover, hold internal tact switch for 7s while connecting.                   |

#### **Emergency Reset For 2541 (Tact Switch)**

If the device fails to initialize or becomes unresponsive during a firmware update, follow this hardware reset procedure (requires opening the device):

1. **Open the back cover** of the IODD.
2. Locate and **press the tact switch** (reset button) on the internal PCB.
3. While holding the switch, **connect the USB cable** to the PC.
4. Continue holding the switch for about **7 seconds**.
5. **Release the switch** and wait for approximately **1 minute** for the system to recover.

#### **Specific Hotkeys (Legacy)**

| Device   | Action       | Hotkey                                                                     |
| -------- | ------------ | -------------------------------------------------------------------------- |
| **2531** | Rescan Files | Long press **Jog Up** (3s)                                                 |
| **2531** | Power Down   | Long press **Jog Down** (3s)                                               |
| **2531** | Enter Menu   | Long press **Jog Center** (3s)                                             |
| **2531** | Detach All   | Long press **Back/Up** (3s)                                                |
| **2541** | Select File  | **\[5]** or **\[6]** (**\[6]** maintains loading state on newer firmware)  |
| **2541** | Power Down   | Long press **\[1]** (3s)                                                   |
| **2541** | Reboot       | Long press **\[3]** (3s)                                                   |
| **2541** | Rescan Files | Long press **\[4]** (3s)                                                   |
| **2541** | Detach All   | Long press **\[7]** (3s)                                                   |
| **2541** | Disable WP   | Long press **\[0]** (3s) - Reboot and temporarily disable Write-Protection |

* **Tip (2531)**: On firmware 1558 or higher, the loading state is saved automatically. For older versions, use the Power Down hotkey to save the state manually.
* **Tip (2541)**: Button **\[6]** for maintaining loading state requires firmware 6(7)9-05 or higher.

#### **Startup Keys (2531 Only)**

During startup (when connecting the USB cable), holding the following keys will force a specific mode:

| Key             | Resulting Mode                                |
| --------------- | --------------------------------------------- |
| **Jog Up**      | Start in **CD-MODE**                          |
| **Jog Down**    | Start in **HDD-MODE**                         |
| **Jog Center**  | Start in **DUAL-MODE** (Resets loading state) |
| **Back Button** | Start in **Write-Protected** mode             |

#### **Firmware & Partition Limits (Legacy)**

* **NTFS vs FAT**: Separate firmware versions exist (ending in **N** or **F**) depending on the first partition's file system.
* **6x vs 7x Versions (2541)**: `7x` versions include enhanced security against brute-force password attacks. **Note**: Data must be backed up when switching between `6x` and `7x`.
* **2TB Limit**: When using virtual drive functions (ISO/VHD), a **maximum 2TB partition** size is supported on 2531/2541/MINI models.

***

### Advanced VHD Naming Conventions (IODD 2531 / 2541 Only)

{% hint style="warning" %}
**Model Limitation**: The following tips for controlling modes via filenames (**`&D`**, **`&DW`**) apply **only to IODD 2531 and 2541 models**. These features are not supported on newer models like ST400, LK100, or MINI PRO.
{% endhint %}

For legacy models (2531/2541) and specific automated workflows, the filename of a VHD can control the IODD's behavior upon mounting:

* **Standard Mounting**: `filename.VHD` or `filename.VMDK` (Mounts as a fixed disk). iODD supports fixed-size VMDK files (can be created by renaming a VHD to VMDK).
* **Removable Mounting**: `filename.RMD` (Mounts as removable media/flash drive).
* **Dual Mode (Write-Protected)**: Append **`&D`** to the filename (e.g., `Win2Go&D.VHD`). Mounts in Dual Mode with the physical HDD write-protected.
* **Dual Mode (Write-Enabled)**: Append **`&DW`** to the filename (e.g., `Win2Go&DW.VHD`). Mounts in Dual Mode with the physical HDD write-enabled.

#### **Virtual FDD Support**

IODD supports uncompressed floppy disk images in **IMA, IMG, BIF, or VFD** formats. If using `.IMG`, `.BIF`, or `.VFD`, rename the extension to **`.IMA`** for best compatibility.


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