## One way in which technology appears to be moving forward.

One of the facts which I only posted about a few years ago, was the existence of external sound devices, which effectively acted as an external, USB-connected sound card, and, whether they could be made to work with certain Android software. That particular sound device had as main feature, studio-quality sound (96kHz, 24-bit).

Well, there is a more recent way to accomplish approximately the same thing:

I should mention in what context this later technology presents itself to the users of mobile devices:

Much as Apple rolled out smart-phones with no traditional, 3.5mm stereo headphone jacks, Samsung has rolled out similar tablets, where the universal connector-type of the latter, is a USB-C port. The ‘Tab S6′ is an example of that. Thus, because some users do want to connect ‘wired’ headphones to this tablet, it’s suggested that users buy a so-called “dongle”, that adapts the USB-C port on the tablet, to a female, 3.5mm stereo phone jack, even the microphone feature of which seems to work. This one cost me CAD 22, including 1-day delivery.

A simple question which some people might have, especially if they are deeply mired in the analog days, and in the technology which existed in the 1970s and 1980s, could be: ‘Does such a dongle just connect the analog pins of the headphone socket, directly to the pins of the USB socket? If not, what exactly does it do?’

The correct answer to that sort of question would be the fact that, as small as that end of the dongle is, on the USB-C side, there is a tiny chip. With that tiny chip, the manufacturers have added a completely unpredictable amount of complexity, to how the dongle might work. Chips exist that have 100,000 transistors. And chips also exist that have 1,000,000 transistors, although that last type of chip is less common, and exists in spectacular cases, such as CPUs, GPUs, etc..

What this means is that, in theory, the chip in this adapter could do everything that the ‘Focusrite 2i2′ external sound card was able to do. But, that’s in theory. There are two important ways, in which it will fail to do so, at least at the time I’m writing this:

1. The accuracy of that chip is in doubt, And
2. The protocol with which the adapter communicates with the USB-C port of the mobile device, which is actually referred to as its USB Profile, has not been made backwards-compatible with the older generation of external sound cards…

(Updated 6/28/2020, 12h45… )

## Testing the Focusrite Scarlett 2i2 external sound device, with my Samsung Tab S Tablet

I have tested, whether this external USB recording tool, works with my Samsung Galaxy Tab S Tablet, using a ‘StarTech.com’ OTG adapter. The results were resoundingly affirmative.

In This Earlier Posting, I had tested the same USB Sound Card, with my Samsung Galaxy S6 Smart-Phone. At that time, an attempt also to use it with my Tab S tablet had failed. In order to get the Scarlett 2i2 to work with the Tab S, the following two conditions need to be fulfilled:

1. The amount of current that the USB Slave Device may draw, needs to be reinforced, in principle, with a self-powered OTG adapter, or with a similar arrangement. The ‘StarTech.com’ is Not a self-powered OTG adapter, and with it, the Scarlett 2i2 is bound to draw too much current, for the likes of the Tab S. It was after all meant as an audio workstation workhorse, and not as a replacement for a simple USB Microphone.
2. The Master / Host Device, the Tab S, needs to have the correct drivers.

Condition (1) is something I was able to fulfill for now, in a roundabout way. I bought a ‘j5create USB 3.0 4-Ports Mini HUB’, with the part number ‘JUH340′. This is a self-powered hub by default, with its own power cord, and has Type A USB connectors up-stream and down-stream. Granted, it has a special up-stream cable, that connects to the hub with a special connector, just so that the user does not get this socket confused with the down-stream sockets. But then, the far side of that cable has a standard Type A USB jack.

This USB jack can be plugged, into the far side of the OTG adapter. Since the hub is self-powered, the current requirements of the Scarlett 2i2 are met by it, and not by the OTG adapter, and thus not by the micro-USB port on the Tab S, the latter of which now faces a minimum current load.

## Retailers find it hard to Define what a USB Y Cable is supposed to be.

In This Posting, I wrote that I was looking for an OTG cable, with a separate power jack, preferably also a Male USB A. One possible alternative to that, would be a Female USB A to 2x Male USB A, with one of the Male USB jacks distinctly for Power, and the other distinctly for Data.

The problem with this, is that although both products exist, I don’t own one of either.

Further, the potential sellers of these cables do not understand what they are selling. They tend to give jumbled descriptions, thinking that if the wording of the description follows a certain trick, this is the correct cable.

Of course, some Electrical understanding allows certain people, to define each type of cable, and thus to name them in a meaningful way. However, often vague descriptions are given, that sound like they might be the correct product, but closer inspection reveals a next-to-useless cable. The most common error, is a Type A Female, connected to 2 Type A Males, in a completely symmetrical way between the Males. The cable is already useless to me, if they are asymmetric in fact, but not labeled in any way that tells me which Male Type A goes into my power source, and which goes into my OTG cable.

Another type of USB cable which does not suit my needs, is a kind of wiring-bus between several connector-types, but which connects every wire, to each connector… In theory, some other user might use that as a converter, between any two connectors.

The correct USB Y Cable costs C$40, while a power-spliced OTG Adapter costs C$ 8.

Now, I have just ordered both types of cable, so that if the OTG is somehow hamstrung software-wise, the USB Y is likely to offer a solution that will still work. Also, it might always come in handy, just to have a USB Y on-hand.

Dirk

## Testing the Focusrite Scarlett 2i2 external sound device, with my Samsung S6 Smart-Phone

I have tested, whether this external USB recording tool, works with my Samsung Galaxy S6 Smart-Phone, using an ‘StarTech.com’ OTG adapter. The results were mixed. In An Earlier Posting, I had tested whether this external USB Sound Card, works under Linux. And the answer to that question was a resounding Yes.

When we plug an OTG adapter into a smart-phone or tablet, this puts the mobile device into Master / Host Mode, that would otherwise normally work in Slave Mode. Thus, we can then plug in a USB storage device, and hopefully have that recognized, while by default, we can only plug our mobile device into a computer, and have the computer recognize this mobile device, as the storage device.

But it is also plausible to connect other external devices to our mobile device, when using an OTG adapter. All this happens because the OTG adapter itself contains an additional chip, that gives it the ability to act as a USB Host. Whether such external devices will work or not, generally depends on two factors:

1. Whether the micro-USB port on the mobile device can output enough current, to supply the external / Slave device, and
2. Whether the mobile device possesses the drivers needed, for the USB device in question. Under Linux, this last question is more likely to be answered in the affirmative.

The OTG adapter I was using, uses its micro-USB side as the only power-supply. This means that if the connected device draws a full 500mA of supply current, we are pushing the limit, that is generally set for USB 2.0  PC ports.