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USB2.0 Loop Back Tester
High quality, loopback plugs for USB 2.0 troubleshooting and USB2.0 testing. (Also works on USB 1.0/1.1 ports)
USB Loopback plugs can be used to help diagnose, troubleshoot and load test your PC. When used with the BurnInTest Professional software package V4.0 or higher and the included USB2Test Software, it is possible to.
- Quickly check if a USB port is powered
- Check that data can be sent and received from the port
- Check USB errors rates and transmission speed (up to 480Mbits/sec)
- Measure the level of recovered data (retransmitted frames)
- Verify that the system remains stable under long periods of load
- Test that USB support in Windows has been correctly installed
- Test self powered USB hubs and PC ports function correctly
- Check USB cabling
- Concurrently check multiple USB ports at the same time.
- Benchmark your PC's USB ports & hubs.
- Check if your PC ports are high speed 480Mbits/sec (USB 2.0), or full speed 12Mbits/sec (USB 1.x) via a LED
- Active loopback plugs are the quickest, most effective way to verify that a PC's USB ports are working correctly. The
- Red, Green and Yellow LED's on the front of this USB adapter plug provide a quick visual indication of I/O activity and if the USB bus is powered. This will dramatically improve the troubleshooting and diagnostic ability of computer technicians and system integrators, who have previously been working blind.
In benchmark mode, the device is capable of reaching the maximum defined transfer speed for USB2.0 (480Mbit/sec). Note: Testing has shown that most PC's can not attain speeds much above 300Mbits/sec and performance will vary depending on your motherboard, CPU and other USB devices connected to the PC.
Up to 10 of these USB test plugs can be simultaneously connected to a PC providing that free USB ports are available on the PC or on a down stream hub and sufficient power is available.
These plugs are unique! They are the only true USB 2.0 loop back adapters on the market and have been especially designed for use with our BurnInTest Professional software package or USB2Test stand alone software supplied with the plug. They do not require an external power supply and do not require a connection to any other port on a PC. Each plug also has its own serial number stored in EPROM, on the plug, so it is possible to identify each plug when multiple plugs are connected.
Each plug also contains its own CPU and executes its own firmware (which can be upgraded in the future by download)
Technical Specifications
- USB standard: 2.0 HighSpeed and FullSpeed
(and is backward compatible with USB 1.1 and 1.0)
- Plug and play: Compliant
- Physical connector: Standard 4 wire USB
(2 x Balanced Signal, 1 Voltage [VBUS], 1 Ground [GND])
- USB Transfer modes: Bulk
- Voltage: 4.4V - 5.25V. (No external power supply is required)
- Current: 400mA (typical operation)
- Clock speed: 24Mhz
- Device memory: 8KB
- Case: High impact MABS plastic
- Size: 65mm x 50mm x 20mm (2.5 x 2.0 x 0.8 inches)
- Weight: 35g (1.3oz)
- Indicators:
Orange LED = USB2.0 (HighSpeed ) or USB1.0 (FullSpeed ) indicator
Green LED = Transmit data
Red LED 1 = Power from USB bus
Yellow LED = Receive data
Red LED 2 = USB bus transmission error indicator
- EMC standards: AS/NZS 3548:1995, EC
- Storage Temperature: -20 ºC to + 70 ºC
- Usage Temperature: 0 ºC to + 45ºC
- Max speed: 480 Mbits/sec
Cabling
The USB cable is not sold with the plugs . You will need to supply your own standard USB cable. While just about any USB cable will work, it is better to select a quality high speed, shielded, USB cable when testing. Note that some of the cheaper USB cables are not shielded and thus are not recommended. The cable must be shorter than the 5m allowed in the USB standard. If a USB connection is required beyond 5m one or more hubs are required to extend a USB connection. We have noted during our testing that longer cables are more likely to have higher error rates.
Compatibility
Windows 2000 and XP are supported.
Window 95, 98, ME, NT4, Mac & Linux are not supported.
In order to use the plugs the stand alone test software USB2Test is required. (see below)
USB 2.0 and 1.1 ports are supported. (when connected to a USB 1.1 port only the lower speed, USB 1.1, mode will be used)
Plugs will work with motherboard USB ports and hub connected USB ports.
USB2Test Software
Name: USB2Test
Version: V1.0 build 1005
Release Date: 23/September/2004
Price: Free with the purchase of a USB 2.0 loopback plug
Platforms: Windows 2000 and XP
Requirements: 16MB RAM, 2MB Disk space
Download Size: 122KB (1min @ 33kbits/sec)
Overview:
USB2Test is an easy to use Windows based application that allows users to quickly check that all the USB ports on their PC are functioning correctly and allows them to determine the maximum speed of these ports (and hence whether they are configured as expected). USB2Test is designed for use in conjunction with our USB 2.0 loopback plug and will test both USB 1.x and USB 2.0 ports at Full-speed (up to 12Mb/s) and USB2.0 ports at High-speed (up to 480Mb/s) rates.
Feature description:
USB2Test when used together with a USB 2.0 loopback plug has the following features:
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A loopback mode where a user controlled (start/stop) number of data packets may be looped for reliability testing.
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A benchmark mode where the maximum read and write speeds are determined for a user selected port. Ten packets are written out the USB port and ten packets are read from the USB 2.0 loopback plug.
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Selection from a list of USB ports that have USB 2.0 loopback plugs connected.
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User selectable loopback data of user specified constant data, incrementing sequence data or random data.
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User selectable loopback verification or no verification.
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Saving of loopback and benchmark result data to a user specified file.
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The display of port information, such as, HighSpeed (up to 480 Mb/s) or FullSpeed (up to 12Mb/s).
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The display of loopback results, such as the number of packets looped, number of verification failures and the number of recoverable errors (ie. re-transmission).
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The display of benchmark results, such as the result for each of the twenty packets sent/ received and the overall benchmarked result.
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A comprehensive help file.
The USB2Test utility can only be used with the our USB2 loopback plug.
Testing using the USB 2.0 loopback plug - software features
Feature USB2Test V1.0or above
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HighSpeed (USB 2.0) or FullSpeed (USB 1.x) port indication
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Yes
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USB 1.x and 2.0 loopback testing
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Yes
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USB 1.x and 2.0 Benchmarking
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Yes
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Supports USB 2.0 loopback plug
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Yes
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Supports simultaneous testing of multiple USB ports
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No
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Support simultaneous testing of multiple PC components
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No (USB only)
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Scripting of test runs
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No
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Logging Yes.
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Basic results
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Error reporting Yes.
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Basic errors.
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User configuration of loopback test data
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Yes
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Windows 2000 and XP support
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Yes
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Windows 95, 98, ME, NT, Linux, Mac support
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No
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Screen shot: The main window
The above diagram shows the results display following a successful loopback test and a Benchmark test.
USB2.0 Loop back plug FAQ
Q. Which operating systems are these plugs compatible with?
The drivers are currently only available for Windows 2000 and XP. Also, Microsoft doesn't support USB2.0 in Windows NT, 95, 98 and ME. Mac and Linux are also not supported.
Q. Do I need a device driver to use these plugs ?
A device driver is required. It is supplied with the plugs on a floppy disk or it can be downloaded. Windows will prompt for the device driver the first time a plug is used. The installation process is covered in the install guide.
Q. Why does USB2Test have a limit of only 1 plug in use at the same time ?
The physical limit with USB is 127 devices connected with a tree of USB HUBS. However the USB2Test software that is used with the USB plugs will only test one port at a time If you have a special application that requires more than one plug simultaneously in use please contact us.
Q. Does the PassMark USB 2 loop back plug appear in my Device Manager as a new USB Device ?
Yes, you can see the devices in the Windows device manager. They appear with the label, "USB2 Driver (PMUSB.sys)".
Q. Can the plugs also be used on PCs with older USB1.1 ports ?
Yes, but they will not use the additional bandwidth available in 2.0.
Q What is the meaning of the 5 LEDs on the device
Q. Can the USB2 plugs be used to test bus powered USB hubs?
In most cases bus powered USB hubs will draw too much electrical power from the PC's USB ports to support additional USB2 devices being connected into the hub. We recommend using self powered USB hubs when required (self powered hubs come with their own power supply).
Q I get a error message "This device cannot start (code 10)" what does this mean?
If a PC's USB port has insufficient power to start the USB2Test device in High-Speed mode you will receive a HID device driver error message "This device cannot start (code 10)". Disconnect other devices from the same USB root hub to make more power available for the device. This will typically occur when a USB2 test device is plugged into a bus-powered hub or a laptop running from battery power. Switch over to a self-powered hub or connect the laptop to a mains power supply.
Q. What Windows patches do I need to correctly support USB2 on my PC
There are a large number of problems found by Microsoft with different configurations of operating systems and the USB2 Host Controllers found on various PC motherboards. It is important to ensure that you have the latest device drivers contained in the latest Microsoft Service Packs and the latest O/S patches.
Q. The USB2 loopback plug disappears when the PC is placed into hibernation, why?
The current version of the USB2 loopback plugs device driver does not support Hibernation. The device should be unplugged prior to placing a PC in Hibernation.
Q. The USB2 loopback plug disappears when the PC is placed into standby and I am using Windows 2000, why?
The current version of the USB2 loopback plugs device driver does not support standby in Windows 2000. On Windows 2000, the device should be unplugged prior to placing a PC in Standby.
Q. The benchmark speed reduces as I add USB devices, why?
As you add USB devices to the (Universal Serial) Bus you will observe a reduction in maximum performance of each USB device. This is to be expected and is due to increasing overheads on the bus as more devices are added. The overheads introduced from each USB device on the bus reduces the number of bytes that can be utilized by other USB devices during a frame (i.e.. less data blocks can be transferred per frame ). Overheads include packet organization, framing information, polling, clock adjustment and reserved time.
Q. What type of USB data transfer type does the USB 2.0 loopback plug use?
Bulk USB transfers are used. Bulk transfers guarantee accuracy of the data through detection of erroneous data and automatic retries.
Q. The red Error LED goes on. What does this mean?
Low level USB errors that lead to retransmission are counted by the USB 2.0 Loopback plug. Data verification errors are also counted while loopback testing with the USB2Test software. The red Error LED will go on:
i) When verify data has been selected and the data received by the USB2Test application is not the same as the data sent.
ii) The number of "recovered bus errors" during a loopback test reaches a defined threshold of 4 "recovered errors" per block (In FullSpeed, 12Mb/s, a block is 64 bytes; in HighSpeed, 480Mb/s, a block is 512 bytes).
iii) The number of "recovered bus errors" when no tests are being run and the USB loopback device is out of its initialization mode (i.e. you have run at least one loopback/benchmark test since plugging the USB2 loopback plug in) is greater than 4. These "recovered bus errors" occur with USB packets used at the system level (e.g. USB Host Controller requesting status information from the USB2 plug for plug and play purposes) as well as data packets.
A "recovered bus error" is a term we have used to group errors that are detected at a low level and that lead to the packet being retransmitted. This is normally not visible to the user, we display this to help identify (for example) faulty cables or cables that are too long, where the number of recovered bus errors will be much higher than relative to using a higher quality/shorter cable. The errors are either bit stuff violations, PID check violations or CRC errors (Please refer to the USB 2.0 specification for details on these error types).
Q. What maximum speed should I expect from my USB port?
USB2.0 High-speed is normally quoted as 480Mb/Sec. USB2.0 and USB1.x Full-speed is normally quoted as 12Mb/Sec. Data rates will never reach these speeds on a real device because some signalling bandwidth is used by packet organization, framing information, polling, clock adjustment and reserved time. On a correctly functioning PC with a single USB device connected, you should typically see measured maximum speed results in the order of approximately:
· High Speed USB2.0 ports connected to the motherboard: 300Mb/Sec.
· High Speed USB2.0 ports connected to a typical PCI card: 150Mb/Sec.
· Full Speed USB2.0 or USB1.x ports connected to the motherboard: 8Mb/Sec.
· Full Speed USB2.0 or USB1.x ports connected to a to a typical PCI card: 6Mb/Sec.
The more USB devices connected to the PC the slower the maximum speed of each of the USB port
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