question

petbor avatar image
petbor asked

Resistance value of switch resistor for OTG + tablet charging enabled together on basic Fire 7" 2015 (= 5th gen., model KFFOWI)

Hi Friends,

pls kindly do you know anyone mentioned resistance value between pin 4 (ID) and pin 5 (GND) of microUSB male plug ?

USB standardized 124 kOhm is unfortunately wrong :(

Thank you very much in advance :)

Have a nice day !

Best regards,

Peter

fire tablet
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Nick Gardner avatar image
Nick Gardner answered

Could you clarify what this is for? Are you asking about the resistance value between pins 4 and 5 of the USB client device attached to the Fire? That should be done by the manufacturer according to the USB spec.

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petbor avatar image
petbor answered

Many thanks for your reply NickG :)

But this is misunderstanding unfortunately.

This is about switchON OTG host + charging of host device together.

By the USB Standard is OTG host function switchedON at host device (phone, tablet, etc.) by short connection = 0 Ohm between pins 4 (ID) and 5 (GND) on microUSB male plug.

If you want swichON OTG host function + charging of host device together, this provide by USB Standard resistance 124kOhms (even is allowed range 119 - 132 kOhms) between mentioned pins 4 and 5.

Problem is, that almost zero producers incl. Amazon respects USB Standard i.e. each, if enable possibility of OTG host + charging host dev. together, select own value of switchON resistance.

I'm asking, if somebody know, which value is valid for Fire 7" 2015 = 5th gen. = model KFFOWI.

Thanks a lot in advance :)

Have a nice day !

Best regards,

Peter

1 comment
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I checked and we do not currently have that information, and I'm not entirely sure that the Fire actually supports accessory charging adapters in the first place. If you are having issues with a specific device, I'd suggest contacting customer support to see if they can help you get it working.

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petbor avatar image
petbor answered

to add:

OTG host function of phone, tablet etc. is switchedON usually by special connector / cable reduction from USB A female type to microUSB B male type.

Unfortunately activation of standard OTG host function (by short circuit = 0 Ohms between pins 4 and 5 at microUSB male plug) terminate charging of host device although charging 5Volts is present.

I need use various USB A male connectored devices together with charging of Fire 7" tablet at same time. This situation should to be solved by right value of resistance between pins 4 (ID) and 5 (GND) & standard charging 5Volts between pins 1 (+5V) and 5 (GND) I hope ;)

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Nash007 avatar image
Nash007 answered

hi, I have the same issue and was wondering if you found the answer? I tried 100k and still no go.

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newuser-9fd6f772-37d7-4698-8284-644aa7ca71c9 avatar image
newuser-9fd6f772-37d7-4698-8284-644aa7ca71c9 answered

I guess you could call me a newbie although I've been messing around with store-bought OTG cables for a few years now I'm just a basic user wear if I have a OTG capable phone or rooted device that recognizes OTG when plugged in I've always known it to be at 100,000 resistor between pins 4 and 5 however I'm having a thought I'm ready to walk out the door right now to go to Fry's Electronics to buy a couple micro USB plugs to make up a custom cable to tether my my Android to my laptop running a Ubuntu 18.04 the beaver version and I'm wondering in my head tossing around the idea of a switched connection at the end of my cable where I can Engage The resist or not ? I'm currently trying to use an alpha network adapter that's programmable to run Kali Linux on my LG Android phone I'm going to create the module people want to call it a driver but I think the correct term is Imago when you're speaking Linux it's going to handshake my device with the network adapter and allow me to go into monitor mode I'm a little out of the realm of the question here but if somebody has any thoughts on my idea please reply thank you

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