USB OTG Cable: Universal Serial Bus On The Go. If you are searching for it, then let’s go in a deep dive and touch first. Here we cover every aspect of OTG.


USB OTG stands for ‘Universal Serial Bus On The Go,’ which is the 1st feature that provides you easy tether between your mobile phone and pen-drive. Its use started in 2001, which allowed the USB devices, like smartphones or tablets, to act as a host, allowing all the USB devices, e.g., flash drives, keyboards, digital devices, or mouse, to be attached to them. The use of this unique device allows other devices to play in the different roles of devices and hosts. Any smartphone can take data or media as being the host device, but at the same time, it can present itself as a storage device on connecting itself to a host computer.

USB On-the-go actually comes up with the idea of a device that is performing both slave and master roles. The device that governs or operates the link of USB is called the master/host, whereas the other one is called the peripheral or slave. The USB OTG has basicallytwo modes, the OTG-A and the OTG-B. The OTG-A is a supplier of power, and an OTG-B is a consumer of power. During default configuration, the device A behaves as a USB master with the device B that acts as a USB slave. The master and slave modes can be interchanged later by using the HNP-host Negotiation Protocol. The first and foremost role given to each part of the device is decided or governed by the mini plug that generally a user puts into the receptacle.

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The USB on-the-go is a part of the 2.0 specification of USB that is also known as a universal serial bus, initially agreed upon in 2001, which was revised quite later. The ‘super-speed On-the-go’ devices, the embedded hosts, and its peripherals are supported by the USB OTG itself and the EHS i.e., a supplement of the embedded host with a ‘USB 3.0’ feature. For any usual USB, all the devices should perform a minimum one role, with the PCs usually madeas to the hosts. E.g., printers generally behave like slaves. If the On-the-go USB is not there, mobile phones usually use the peripheral feature to allow ease in the transfer of data from one computer to another computer. These cell phones cannot be connected to printers or other slave devices just because they work in the slave role. The OTG device gives you the solution to this problem.

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While the master/slave configuration works for a few devices, many other devices can operate either as a host or as a slave. This is, after all, dependent on what is actually being shared via the bus. Take, for example, a commonly used slave device, printer, which we all use.


The OTG  understands that a particular device can work in two modes i.e., slave and host modes. With USB OTG, a device can behave like a ‘peripheral’ when in the slave link. Also, it acts like a ‘host’ when in the master link.  ‘Picking a role’ between the two, host and slave modes/roles, is done by 1 end of the cable with which the connection to the device is established. The device, which is connected to startup or in easy language, 1st end of the cable, is known as  ‘A’ device, and it behaves like the default host while the 2nd end of the cable behaves as the predefined peripheral and is known as the ‘B’ device.

Working of USB OTG Cable

ADP-attach detection protocol provides the user to decide the status of the attachment with an embedded host or an OTG device or any USB device. This type of situation occurs when there is a lack of power to the USB bus that allows two behavior, i.e., displaying the attachment status along with the reaction based on the insertion. It can do this with the help of periodically gauging the magnitude of capacitance over the ends of the USB port.

This also searches for any kind of external device attached to it using a cable or maybe without a cable. Whenever there is an identification of a significant magnitude change in the value of capacitance (C) between the ends, it indicates a device has been attached.

The device ‘A’ gives a power output to the USB bus along with the identification of any nearby connection. While in the meantime, device B will produce Session request protocol and will also wait for the USB bus to get the power. SRP permits two devices in communication to monitor the activity of power. In a normal USB, particularly, the master is allowed to handle this power activity.

It gives the user an overall control over the utilization of power, which can be undeniably regarded as the most important part of battery-operated devices. These types of devices include cell phones, PCs, cameras, etc. The USB OTG or the host can keep the USB link in an unpowered situation, and this can stay like the same until the slave needs power. The USB OTG and the hosts generally posses very less battery power, so keeping the link without power supply helps in increasing battery shelf life.

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As discussed above, the HNP permits 2 devices to interchange their master/slave roles, showing that the OTG is a dual-role device. With the help of HNP in the reversal of roles, the USB OTG device acquires control over data transfer and its scheduling. Therefore, any OTG is good enough to initiate data transfer over the USB bus. The recently launched version of the supplement has introduced HNP polling, that includes the host device to poll the slave in different periods. This occurs during an active power supply session in order to find whether it wants to become a master or not.

Among many applications, the main purpose of HNP is to fit in users who have tethered both the A device and B device in the faulty or wrong configuration. This arrangement is accordingly decided by the task they execute. For instance, take the most common slave printer, which is connected as the device A or as master, but the main problem is that it cannot act like one for a specific device like a camera.

This is because a printer can’t grasp the representing way of a camera to print.  The printer switches to the slave role using HNP with the camera turning into a master so that images and videos stored on the camera can be printed easily without using any cable. The latest USB OTG arrangement can’t surpass a usual USB hub because these are based on electrical signaling through a fixed cable or wire.

USB 3.0

The embedded host and the USB OTG complement to the ‘USB 3.0’, introduces an extra feature, RSP-role swap protocol. This provides the same feature as the HNP is serving, that is the role swapping. This task is executed by extending the normal general process served by the ‘USB 3.0’ feature.

All the devices that are operating nearly according to the supplement and the USB on-the-go with USB 3.0 specification also need to follow the ‘USB 2.0’ supplement. The SS OTG, also known as super-speed USB On-the-go devices, is called for the support to RSP. There is another type of OTG, super speed peripheral capable OTG devices – SSPC OTG is not called for the support to RSP because these can only work at super-speed as a slave. These do not have super speed master, and hence they can only swap its role or mode using HNP at USB 2.0 specification.


  • One usage of OTG is in BlackBerry 10.2 that uses the Host Mode, which Nokia is also using, the OTG in many of its Symbian devices, e.g., Nokia N8, its C6-01 along with E6 and E7. There are many more devices like  Oro, C7, 603, 700, 701, and X7. Few Android devices launched under the brands as SONY and HTC also have this feature. Smartphones from Samsung under android version 3.1 or any of the latest versions are compatible with USB OTG. 
  • Another ‘not a surprising’ application of OTG is the external storage that is put on the top in this list. You will need to connect a drive, and it is all done and ready to use. Hence it will allow you to transfer all kinds of documents.
  • A second application is flash drives. These external drives sometimes work or maybe sometimes not. Transportable flash drives always take power from the mobile phone and may not be able to work all the time. But external hard drives that don’t use other devices to draw power and use their own power source will be a better option.
  • Android 9, along with its few newest versions are compatible and support the Xbox 1 games. Whereas, the older versions like Xbox 360 and few Android devices also work through USB OTG. It is a quiet, secure method as you just need to connect and play the game using a controller.
  • The easy behavior of Android makes it easy for the user to connect it with almost anything according to the needs. You may get delighted after knowing that the Android works well with almost all types of wireless and wired devices. 
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The printers and keyboards work well with the usual USB along with the Android devices. These allow printing without any requirement of wireless connection or any kind of transfer to a personal computer. In any situation, when you don’t have access to WI-FI connection, the USB OTG Cable can be the best option for printing images at homes or in your office.