How to Interface Samsung Galaxy S4 with QXDM

Accessories Required

- Samsung Galaxy S4 Phone with USB Cable

- QXDM and QPST should be installed on the Windows PC.

- USB Driver for the Cell Phone

How to enable the Developer Mode
- Go to Setting ---> More ---> About Device
- Tap on the Build Number until a you see a Developers enable pop up menu option
- Go back to Developers option and select USB Debugging.

Procedure
- Connect the cell phone to Windows PC with the USB cable
- Install Cell Phone drivers
- Once the driver is installed we will see a auto play Pop-up in windows close that pop-up
- Open the device manager on PC by right on "My Computer" then Properties and Device Manager on Left corner
-Check  Universal Serial Bus Controllers ---> Samsung Mobile USB composite Device
             Modems ----> Samsung Mobile USB Modem
             Portable Devices ----> Samsung-SGH-I337
- Right Click on the Samsung Mobile USB Modem and select Properties
-Go to Diagnostics Tab and select Properties
-Click on the Query Mode button, the Modem properties will be shown
-Open  the phone application and dial *#0808# . It will open the USB setting
- From the USB setting select the radio button "RNDIS + DM+ Modem" and Click OK
- Now check the Device manager and it will populate following
    - Modems ---> Samsung Mobile USB Modem
    - Network Adapter ---> Samsung Mobile USB Remote NDIS Network Device
    - Port ---> Samsung Mobile USB Serial Port (COM**)
                      Samsung Mobile USB Serial Port (COM **)
- Open QPST Configuration the mobile device should appear in Active Phone Sections. If it does not appear do following steps
            - Click on the Add New Port
            - We can see the list of Ports
            - Select COM** - USB/QC Diagnostic Port (This port no will be same as Samsung Mobile Serial  Port (COM**)
           - Once we select this we can see the Active Phone Sections show a Phone Connected to COM** Port
- Start the QXDM ---> Go to options ---> Communication ---> Target Port Select COM** and Click OK
- Go to View ---> Select Item View and make a call from the Cell Phone and the Logs will appear

Watt to dBm and dBm to Watt Conversion

What is dBm ?

dBm  is an abbreviation for the power ratio in decibels (dB) of the measured power referenced to one milli watt (mW). It is used in radio and microwave  networks as a convenient measure of absolute power because of its capability to express both very large and very small values in a small value . For example 100Kwatt in dBm can be express as 80dBm and  100 pico watts can be expressed as  - 80 dBm.

Same like dBm there is  dBW, which is referenced to one watt (1000 mW).

Since it is referenced to the watt, it is an absolute unit, used when measuring absolute power. By comparison, the decibel (dB) is a dimensionless unit, used for quantifying the ratio between two values, such as signal-to-noise ratio.

How to Convert Power in dBm and vice versa :

0 dBm equals 1 milli watt. A 3 dB increase in power roughly double the power, which means that 3 dBm equals  2 mW. For a 3 dB decrease, the power is reduced by about one half, making −3 dBm equal to about 0.5 milli watt .

 Power P in watts as m in dBm, or vice versa, the following equivalent expressions may be used:

                  
                   m =  10*Log10 (P*1000)        
                                   or
                    m =  10*Log10 (P) +30                where P is in  watts

and 

         P =  (10 ^m / 10) / 1000                   resultant P is in watts

                           or

        P  =  (10 ^(m-30) /10)

Below is the calculator can be used for the conversion watts to dBm and Vice versa 

Enter a value in Watts and click on calculate to get the value in dBm

• Watts
  Enter value in watts
• Calculate Reset
• Result
  dBm:

  dBm:

Enter a value in dBm and click on calculate to get the value in Watts

• dBm
  Enter value in dBm
• Calculate Reset
• Result
  watts:

  watts:

Some Example of Power in dBm with application are shown in figure :