# How to connect sim slot #2 (micro sim) to secondary CF3 slot?

**URL:** <https://mangoh.discourse.group/t/how-to-connect-sim-slot-2-micro-sim-to-secondary-cf3-slot/712>\
**Category:** mangOH Green\
**Created:** [August 30, 2017, 9:11am UTC](https://mangoh.discourse.group/t/how-to-connect-sim-slot-2-micro-sim-to-secondary-cf3-slot/712 "2017-08-30T09:11:03Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![lyao](https://avatars.discourse-cdn.com/v4/letter/l/e8c25b/32.png) [@lyao](https://mangoh.discourse.group/u/lyao)\
**Post date:** [August 30, 2017, 9:11am UTC](https://mangoh.discourse.group/t/how-to-connect-sim-slot-2-micro-sim-to-secondary-cf3-slot/712/1 "2017-08-30T09:11:03Z")

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HI all,

The default connection is that sim #2 is connected to primary CF3’s uim2. But now I need to connect sim #2 to secondary CF3 because only the chip on this slot supports the RAT of my sim. How can I do this?

I read in the DV4 that it can be done by wither API command and hardware modification. I know the hardware method has to be done by un-soldering and soldering the tiny resistor. Thus the API command way is more suitable for me. But how can I access the pins on the GPIO expander when I code? I need to access the GPIO expander because the UIM signal is located at expander 2’s I/O\_6 and 7.

Thx

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**Author:** ![asyal](https://sea2.discourse-cdn.com/flex016/user_avatar/mangoh.discourse.group/asyal/32/78_2.png) [@asyal](https://mangoh.discourse.group/u/asyal)\
**Post date:** [August 31, 2017, 4:04am UTC](https://mangoh.discourse.group/t/how-to-connect-sim-slot-2-micro-sim-to-secondary-cf3-slot/712/2 "2017-08-31T04:04:26Z")

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You need to control U906\_I07  
You will need to use gpioExpanderServiceGreen to do so.  
An example of using this service is herehttps://github.com/mangOH/mangOH/tree/master/samples/tutorials/mangOH\_Green/gpio/TimerLed

Your binding would be:  
yourApp.yourAppComponent.mangoh\_simGpio -\> gpioExpanderServiceGreen.mangoh\_gpioExp2Pin7

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**Author:** ![lyao](https://avatars.discourse-cdn.com/v4/letter/l/e8c25b/32.png) [@lyao](https://mangoh.discourse.group/u/lyao)\
**Post date:** [August 31, 2017, 12:11pm UTC](https://mangoh.discourse.group/t/how-to-connect-sim-slot-2-micro-sim-to-secondary-cf3-slot/712/3 "2017-08-31T12:11:11Z")

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Thank you very much. I used the binding syntax that you mentioned, but when I run my app (a very simple one seeing whether the pin is output or not), it shows that the binding is missing as shown below:

 ![Screenshot from 2017-08-31 13-59-25](https://us1.discourse-cdn.com/flex016/uploads/mangoh/original/1X/d4b267d907a6aadcf9919391708badf3ed7afefb.png)

Well I’m new to legato and mangoh so do I have to build the gpioExpanderServiceGreen service on the target(the mangoh board)?

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**Author:** ![lyao](https://avatars.discourse-cdn.com/v4/letter/l/e8c25b/32.png) [@lyao](https://mangoh.discourse.group/u/lyao)\
**Post date:** [August 31, 2017, 12:14pm UTC](https://mangoh.discourse.group/t/how-to-connect-sim-slot-2-micro-sim-to-secondary-cf3-slot/712/4 "2017-08-31T12:14:42Z")

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Besides, I also noticed that when the interface instance name that I specified in .adef is too long, after the app is started, a log message shows as follows:

> Jan 6 00:56:04 | _UNKNOWN_[8235]/framework T=main | LE\_FILENAME le\_ref\_CreateMap() 149 | Map name ‘refmangoh\_simGPIO\_ClientHandlers’ truncated to ‘refmangoh\_simGPIO\_ClientHandler’.

Is it normal? Do I need additional care on this issue?