Step 4: Make a Connection
Last updated: January 16, 2009
In this step you establish communication between the test set and user equipment such that measurements can be made. There are two possible ways to make a connection with the UE.
Originating a Connection from the Test Set
The code below illustrates how to make a connection by originating a call from the test set and taking advantage of the repeat paging feature to decrease connection speed.
Origination is performed in a subroutine to allow the use of a timeout separate from the control program's GPIB timeout. This is necessary because the use of repeat paging prevents the use of the state change detector and it's associated timeout (activated by the
CALL:CONN?
hanging query). Therefore, to prevent GPIB bus from hanging indefinitely, which could occur if the UE is not turned on or badly broken, a timeout is implemented in the subroutine on line 2790. The
:SEQ
sequential command is appended to the
CALL:ORIG
command to prevent subsequent commands from being accepted by the test set before repeated pages can be used to originate a connection.
1060 PRINT "Turn the UE on now." 1070 Originate ! Subroutine to originate a connection 2810 SUB Originate 2820 COM /Address/ INTEGER Testset 2830 ON TIMEOUT 7,10 CALL Orig_failed 2840 OUTPUT Testset;"CALL:ORIG:SEQ" 2850 OUTPUT Testset;"CALL:CONN?" 2860 ENTER Testset;Connected 2870 IF NOT Connected THEN 2880 PRINT "Call origination not successful." 2890 STOP 2900 END IF 2910 SUBEND
If the origination fails
By using repeat paging, a situation has been introduced in which the test set will not respond to subsequent GPIB commands until the origination is successful. Once the origination attempt has timed out, it becomes necessary to send the test set a Device Clear remote command (IEEE 488.2 Section 6.1.4.2.6) to free up the remote user interface. In HP BASIC this is the
CLEAR
command, see line 1900. Subsequently, you can send the
CALL:END
command to stop paging the UE and proceed with the control program.
1920 SUB Orig_failed 1930 COM /Address/ INTEGER Testset 1940 CLEAR Testset 1950 OUTPUT Testset;"CALL:END" 1960 PRINT "Origination failed. Check conditions and run again." 1970 STOP 1980 SUBEND
Make a Connection using Test Mode Commands
When the test set is operating in FDD Test Mode, you do not send any commands to the test set for this step. The test set should already be properly configured and transmitting its downlink signal so that the UE can detect and synchronize to it. In this step you either implement a pause in your program and wait for the UE to be manually configured and begin transmitting, or send appropriate test mode commands to configure the UE and begin its transmission.
The method used to synchronize the UE with the test set is proprietary to the UE manufacturer. The test set has no direct control of synchronization when the UE is operating in test mode.
