PhysioTel Digital RF Assessment Procedure Using Ponemah
The RSSI Threshold for the PhysioTel™ Digital Implants and Transceivers (TRX) can be adjusted in the Communication Link Controller (CLC) Diagnostic page in Ponemah. Changes to the RSSI Threshold should only be made if advised by DSI. The guide below explains how to perform a basic RF Assessment to determine the noise level in the room. This information should be provided to DSI Technical Support.
Performing an RF Assessment
Make sure the CLC is set to the frequency you want to scan and that TRXs are connected. Turn off any implants that are set to the same frequency you are checking.
- With the CLC connected to the system, launch Ponemah.
- Select Hardware | PhysioTel Digital Diagnostics…
Note: If using Ponemah v5.20, select Hardware | Diagnostics…
- Choose the CLC from the Name – Model Name (Serial Number) dropdown.
Note: Select the Refresh List button if the CLC does not appear in the dropdown list.
- Select the Settings link from the list view on the left side of diagnostics page.
- Use the RFMode dropdown to select Assessment.
- Select the Save button.
- Select the TRX RSSI History link.
- At the top of the TRX RSSI History page, set Auto refresh page in… to 10 seconds.
- Wait about 60 seconds for the graph below to populate with data related to your noise environment.
- Take a screenshot of the first graph on the page. Send the screenshot by e-mail to DSI Technical Support at support@datasci.com. They will evaluate the graph and send further instructions.
- Click the Settings link.
- Use the RFMode dropdown to select Enabled.
- Select Save.
Tip
A screenshot can easily be taken in Windows 7 using the ‘snip’ tool. Click the Windows ‘Start’ Button. Type snip and the snip program should appear at the top of the list. Using this tool, you can select your assessment graph with a box, and then save it to your hard drive.
Get RSSI Threshold Values
The RSSI Threshold values can be easily retrieved from the diagnostic window.
- Select Implant Commands or TRX Commands, as appropriate
- Enter the Implant ID
- Select "Get RSSI Threshold" as the Implant Command
- Record the last field under HEX and convert this to a decimal value. In the Example below. The Hexadecimal value to convert is 17 (or 0x17)
Example:
Converting Hexadecimal to Decimal or Decimal to Hexadecimal
There are multiple ways to convert the value; An online converter can be used or by using the Windows Calculator. Below are the steps to use the Windows Calculator.
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- Open the Windows Calculator.
- Change the Calculator Type to programmer. Type in the HEX value under HEX or the decimal value under decimal to get the appropriate corresponding conversion.
- In the example above, 17 becomes 11. Additional a decimal of 15 becomes F
- Record this value. If the calculator only gives a single digit or number, insert a leading zero. For example, the output F (a single digit/number) should be written 0F.
Tip
When referring to a hex number, the prefix "0x" is conventionally given to distinguish it from a decimal. For example, a hexadecimal value of 0F is typically written 0x0F.
Evaluating the Graph Yourself (not recommended)
- Examine the first graph on the TRX RSSI History page. Look at the line created by the red dots; this refers to the Mean Noise Floor in your room.
- Record the rough value of the Mean Noise Floor on the graph. In the example below, the Mean Noise Floor is about 9.
- Next, record the width of the standard deviation (green hashes). In the example above, the deviation is about 2 (1 level above the mean and 1 level below it).
- Calculate the necessary RSSI Threshold for the TRX and Implant as follows
- TRX uses a default value of Decimal 18 (hexadecimal 12).
- Implant defaults are determined by the following equation to optimize the listening capability per device:
Noise floor (mean) + 3*(STDEV Noise floor) +1
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- Implant RSSi can vary from Decimal 8 – 16, depending on Region, Model type (Lseries vs Mseries) and part to part variation.
- Last, these values will need to be converted from decimal to hexadecimal. See above
Important
The TRX default value is Hex 12 (18 decimal). Lowering the TRX threshold below the default value should only be done in extreme cases. Lowering the TRX threshold will make the TRX more susceptible to external RF noise, and therefore would most likely increase data loss. Adjusting the TRX RSSI threshold should only be done in cases where the value will increase from it's default value.
Adjusting the RSSI Threshold
Refer to the technical note Adjusting the RSSI Threshold for a Transceiver (TRX) and a Digital Implant for instructions on entering values for the RSSI Threshold.
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