Things to Consider About While Purchasing A USB Isolation Adapter

 Isolated USB safeguards the USB port on your computer from potentially harmful ground loops and ensures the integrity of data in electrically loud environments, such as those that are close to variable frequency motor drives, involve welding, or contain other types of heavy loads. However, this increased security and dependability do not come without an accompanying financial cost. You need to carefully analyze the needs for your bandwidth, downstream power, and cascade connections before deciding to employ a USB isolation adaptor.

Bandwidth

The USB standard has been revised multiple times, each time resulting in changes to the bandwidth, speed, data rate, and other metrics. The USB 2.0 standard specifies three different transfer rates. Low Speed and Full Speed are the two speeds that have been carried over from the previous USB 1.1 specification. High Speed was first made available with the release of USB 2.0. Backward compatibility with the slower speeds of USB 1.1 is another feature of USB 2.0. Because "Full Speed" is considered to be slower than "High Speed," the naming convention can sometimes lead to some misunderstanding.

Finally, "SuperSpeed" USB 3.0 adds even greater data transfer speeds, more power for devices connected downstream, and intelligent charging and powering capabilities.

Bandwidth Limitation for Isolation

The addition of isolation restricts bandwidth to 12 Mbps at "Full Speed." Even though this is still considered USB 2.0, the host controller won't transmit data at 480 Mbps or "High Speed." Automatically, it will slow down to 12 Mbps. Fortunately, 12 Mbps is sufficient for the majority of industrial applications. You shouldn't use isolation if you need 480 Mbps "High Speed," otherwise you might think about using USB 3.0 SuperSpeed. USB 2.0 Hubs and USB 3.0 SuperSpeed Hubs are available from Coolgear.

It's crucial to remember that even if every USB version is backward compatible with its predecessors, it cannot help older devices run faster. A USB 3.0 port, for instance, can communicate with a USB 1.1 or 2.0 device, but only at the device's native USB 1.1 or 2.0 speed.

The opposite is also accurate. Only USB 2.0 speeds are possible when a USB 3.0 device is connected to a USB 2.0 port. Both the connected device and the host USB port must support USB 3.0 to receive full speed.

Additional USB isolators with one or two ports are available from Coolgear. The fixed speeds for the UH4xx product series are either 12 Mbps or 1.5 Mbps. This is a crucial distinction to make because "Full Speed" devices cannot be used with "Low Speed" isolators, and vice versa.

A USB hub chip is also present in the UHRxx isolators. They become "smart" by having the hub chip since they can choose between 1.5 Mbps of "Low Speed" and 12 Mbps of "Full Speed" on their own. None of these isolators can function at 480 Mbps "High Speed." 

Power

Another factor to consider is the required power. Both the four-port and seven-port Coolgear isolated USB hubs require an external power supply. As a powered hub, it supplies 500 mA per port for powering downstream devices.

Isolators of the UH201 and UH40x series lack an external power option and are restricted to 100 mA downstream power.

The BB-UHR204 model has the additional capability of working in USB bus-powered mode. In this mode, each port's downstream current is limited to 100 mA.

The models UHR401 and UHR402 must be powered by an external source and offer 500 mA per port.

Cascading

USB isolation limits the number of hubs that can be cascaded. This is a rare use, but it merits examination.

The USB 2.0 standard allows up to five hubs to be cascaded. This includes the USB controller hub included within the PC. When an isolated USB hub is used, the isolation chip introduces a propagation delay comparable to that of a single USB hub. Therefore, one hub is counted as two hubs in the cascade. Consequently, a single USB host controller can only accommodate two hubs.

According to USB 3.0 isolation requirements, if a USB 3.0 hub is connected to a USB 2.0 host, downstream ports will not accept USB 3.0 devices. Furthermore, multiple units cannot be cascaded.

The Bottom Line

USB Isolation adapter safeguards your computer's USB port from hazardous ground loops and ensures data integrity in electrically loud conditions, such as in the vicinity of a variable frequency motor drive, welding, or other heavy loads. However, this additional security and dependability do not come for free. Before selecting to employ USB isolation, you must analyze the aforementioned factors, including your bandwidth, downstream power, and cascade needs. Once you calculate your requirement, opt for it as per your budget.