StarTech USB2TYPEM USB-A to 5.5mm Barrel Power Cable

Overview

The StarTech USB2TYPEM is a 3-foot (0.9m) USB 2.0 Type-A to 5.5mm/2.1mm barrel power cable designed to deliver regulated 5V DC at up to 0.9A from any standard USB host port. If you have a router, NVR, small IP camera, or peripheral device rated for 5V DC with a 5.5mm OD / 2.1mm ID barrel connector and you need to power it from a nearby USB port rather than running a separate wall adapter, this cable is the direct solution. The USB2TYPEM eliminates the need for a dedicated 5V power brick in installations where USB power is already accessible — saving wall outlet space and reducing cable clutter at rack edges or workstation deployments.

The cable measures just 3 feet, keeping runs tidy in tight enclosures or desk-mounted equipment. At 0.8 oz (24g), it adds negligible weight to any installation kit. The center tip carries positive polarity, which matches the vast majority of barrel-connector consumer and commercial peripherals — always verify your device's polarity requirement before connecting.

Key Features

• 5V DC at up to 0.9A output: Draws from the USB 2.0 port's power bus (capped at 0.9A per USB 2.0 spec), making it compatible with any compliant USB host — desktop PCs, powered USB hubs, NVR rear panels with USB ports, or USB power adapters. Devices drawing more than 0.9A will not operate reliably; check your device's current spec before deploying.
• 5.5mm OD / 2.1mm ID barrel connector (Size M, positive center): This is the most common barrel connector size in commercial security and networking equipment. Positive center polarity is the industry default — but non-standard devices exist, so confirming polarity on your target device is a required step before first use.
• USB 2.0 Type-A connector on the source end: Fits any standard USB-A port — no drivers, no data negotiation, purely power delivery. Works with any USB-A host regardless of USB generation (USB 3.x ports are backward-compatible with USB-A connectors for power).
• Aluminum-mylar foil with braided shielding: Dual-layer shielding keeps conducted interference off the power line — useful in rack environments with dense switching power supplies or near RF-emitting equipment where an unshielded cable might introduce noise artifacts on sensitive analog inputs.
• PVC cable jacket: Flexible and durable for permanent or semi-permanent installations. The 3ft (0.9m) length is intentionally short — if your USB source and target device are more than arm's reach apart, plan for a USB extension or reposition the USB host.
• Operating range -20°C to 60°C: Handles the thermal range found in most indoor equipment rooms and light-industrial enclosures. Not rated for outdoor-only environments subject to freezing without enclosure protection.
• Compact form factor (0.6 in wide × 0.3 in tall): The slim connector head fits in congested port rows without blocking adjacent USB ports — a practical detail when working on populated rack-mount USB panels.

Integration and Compatibility

The USB2TYPEM is a passive power cable — there is no active circuitry, voltage regulation beyond what the USB host provides, or data path. Compatibility is determined entirely by three factors: (1) the target device requires 5V DC input, (2) the barrel connector is 5.5mm OD / 2.1mm ID, and (3) the center tip must be positive. Devices with reverse polarity or different barrel sizes (e.g., 5.5mm/2.5mm ID or 3.5mm/1.35mm) are not compatible.

Common compatible device classes include small IP cameras with USB-powered auxiliary inputs, access control readers, small wireless access points, LED lighting controllers, and portable network appliances rated at 5V/0.9A or less. For NVR installations where a small satellite device needs local 5V power from the recorder's USB port, this cable provides a clean, permanent solution without a separate adapter. If your deployment involves PoE-powered cameras or devices drawing more than 0.9A, see your PoE switch options instead — USB bus power is not a substitute for PoE in those scenarios.

Review the StarTech accessory catalog for additional cable adapters and power solutions. For installations where cable length or connector type varies, StarTech offers a range of power cables and adapters suited to different barrel sizes and source voltages.

Frequently Asked Questions

Q: What barrel connector size does the USB2TYPEM use?

A: The USB2TYPEM uses a Size M barrel connector with 5.5mm outer diameter and 2.1mm inner diameter, positive center tip. Verify your device matches all three parameters before connecting.

Q: How much current can the USB2TYPEM deliver?

A: The cable delivers 5V DC at up to 0.9A (900mA). This is the maximum current available from a USB 2.0 port under the USB specification. Devices requiring more than 0.9A will not function reliably from this cable.

Q: Will the USB2TYPEM work plugged into a USB 3.0 or USB 3.1 port?

A: Yes. USB Type-A is backward-compatible across generations for power delivery. The USB2TYPEM draws only power from the port — there is no data transfer involved — so USB 3.x ports supply compatible 5V power through the same Type-A receptacle.

Q: Can the USB2TYPEM be used outdoors?

A: The cable is rated for operating temperatures from -20°C to 60°C and is not assigned an IP rating. It is suitable for sheltered indoor and light-industrial environments. Outdoor use is not recommended without enclosure protection from moisture and direct exposure.

Q: Is the USB2TYPEM compatible with devices that have reverse (negative center) polarity?

A: No. The USB2TYPEM is wired with positive center tip polarity. Connecting it to a device requiring negative center polarity will not power the device and may cause damage. Always confirm your device's polarity requirement before use.

Q: How long is the USB2TYPEM cable?

A: The cable is 3.0 feet (0.9 meters). If the distance between your USB source and target device exceeds this, you will need a USB extension cable between the power source and the USB2TYPEM.

Jerry Tildsen

The USB2TYPEM comes up regularly in small-footprint security installs where a 5V peripheral — a card reader, a small wireless bridge, or an auxiliary sensor — needs permanent power and the only available source within 3 feet is a USB-A port on an NVR or managed switch. The 0.9A ceiling is the spec that determines whether this cable works for your application or doesn't, so that's the first number to check against your device's nameplate.

Technical Highlights:

• Dual shielding (aluminum-mylar foil + braid): In mixed-signal rack environments with switching supplies nearby, unshielded power cables pick up noise that can manifest as ripple on sensitive inputs. The USB2TYPEM's two-layer shield reduces that risk without requiring separate ferrite treatment.
• 5.5mm / 2.1mm barrel, positive center: This spec combination covers the overwhelming majority of commercial 5V barrel-connector peripherals. The positive center convention is standard, but I've seen enough reverse-polarity devices in the field to make checking the device's documentation a non-negotiable first step.
• Operating temperature -20°C to 60°C: Covers typical indoor equipment room ranges comfortably. At 60°C upper limit, it also handles warm rack enclosures that would degrade cheaper PVC cables faster.

Deployment Considerations:

• At 3.0 ft (0.9m), this cable assumes the USB source and target are co-located — plan your rack layout or workstation layout accordingly before committing to it. A USB-A extension adds reach if needed, but introduces another connection point.
• The 0.9A cap is a hard ceiling set by the USB 2.0 spec on the host port side, not just the cable. If your device draws 1A or more at startup, it will likely brown-out or fail to initialize — no amount of cable quality changes that limit.

The USB2TYPEM fits best in permanent rack or panel installations where a small 5V peripheral — access control reader, sensor node, wireless bridge — lives within arm's reach of a USB-A host port and the integrator wants to avoid an extra wall-wart adapter. It's a single-purpose tool for a specific wiring problem, and it solves that problem cleanly when the specs align.