Nokia Net Monitor description (DCT3)

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Test 17 – BTS (Base Transceiver Station) Test (active)

Available in: 2100, 2110i, 2140, 3330, 5110, 6150, 6210, 7110, 8210, 8250, 9xxx

It allows you to lock the phone to a BTS of your choice, or more specifically, a radio channel of your choice.

Test screen	Help screen

Second Line: Shows the status of the BTS Test. Note, this status does not always show the correct status at the time of viewing the display. Can be “OFF”, “ON” or “REQUESTED”.

CH: Shows the radio channel for BTS Testing. If no valid channel is specified in SIM location 33, “xxxx” is displayed.

BTS Test allows the user to specify a channel for testing. Once the BTS mode is engaged, only that channel is used for idle mode and active mode (although the phone is allowed to frequency hop). The phone ignores neighbour information broadcast by the tested BTS, and will not handover during call to another cell. If the phone moves out of range of the tested BTS, the phone will show no coverage and will enter NSPS (No Serve Power Save) mode until it finds another BTS using the specified channel for its BCCH. Obviously, the channel requested must be a BCCH carrier (the carrier on which information about the cell is broadcast, which phones listen to in idle mode).

To use the BTS Test mode, the radio channel to test must be entered in SIM memory location 33’s phone number (don't know position in Nokia 9xxx). The name can be set to anything, however something like “BTS Test” would be appropriate. To find out how to store specific values to SIM memory see “How to write number to a specific SIM position?”. Then, jump to this test. The display will change from “BTS TEST OFF” to “BTS TEST REQUESTED”. The channel number should display the channel number you have chosen.

If the channel number displayed is “xxxx”, it means you probably have entered an invalid channel number. It also could mean the SIM card could not be read (which seems to happen sometimes after a power on). If this is the case, jump to this test to cancel the BTS Test, wait a few minutes for SIM to respond (i.e. check the phonebook for the BTS TEST entry), and then retry the test.

The state “BTS TEST REQUESTED” means the BTS Test is not actually happening, however it has been ‘scheduled’ and will occur the next time the phone loses signal. There are several ways to do this. You could attempt to disconnect the antenna or move the phone way out of coverage, often neither of these are practical or possible. Most sources recommend turning the phone off, and then back on again, which is pretty easy. There is one other way to do it however, and that is to used “Test 19 – Change Behaviour for Barred Cells” to kill the signal. See the test for more information, however to briefly describe the procedure, jump to Test 19 after requesting a BTS Test. The display should change from “CELL BARR ACCEPTED” to “CELL BARR REVERSE”. If not, keep jumping until it does display “CELL BARR REVERSE”. Then, attempt to communicate with the network (i.e. dial a number and then a split second after pressing ‘Call’ cancel the call). Within seconds the signal should drop. To regain the signal, and enter the BTS Test, jump to Test 19 until it displays “CELL BARR ACCEPTED”. Note this procedure may not always work if there are barred cells in the area.

You can see that the BTS Test is active by viewing “Test 3 – Information about Serving Cells and Neighbours”, and you will note only the serving cell entry (the top line) is present, the neighbours are all ‘x’s. If you view Test 17 (don’t jump to it), it will also display “BTS TEST ON” and the channel number.

To disable the BTS Test, you jump to the test again, however it will still display “BTS TEST ON”. Once again, this ‘schedules’ to turn the BTS Test off the next time the phone loses coverage. One way to do this is to simply let the phone lose coverage, since it is locked to a channel, it probably will at some stage. When this does happen, the phone will search for other channels and return to normal operation. Alternatively, you can power the phone on and then off, or use the Test 19 method as described above. When the BTS Test is off again, it will display “BTS TEST OFF” and the channel number currently saved in the SIM memory.

BTS Test mode is a very powerful test, and can sometimes help in a number of situations, or is fun to play around with.

A word of warning, however. BTS Test can have problems with some phones, such as earlier software on the 6210 and 8250, but there are most probably others. In some cases, I have heard, the phone might display “CONTACT SERVICE”, and can be fixed by re-flashing the software. In other cases, starting with a SIM card of a different network operator can fix the problem. Use this test at your own risk.

For some models of phones, particularly some older ones such as the 5110, this test exhibits unusual and possibly problematic behavior when paired up with Test 19 (to drop the coverage). In such a case, it is better to resort to power cycling the phone to toggle BTS Test status.

Also, on some phones, such as the 5110, the status “REQUESTED” is not displayed (it is left as “OFF”). The behavior of the test is otherwise normal.

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WAP-gateway IP: 79.186.244.250
Port: 9201