Last updated: December 3, 2008
This section is only applicable to the lab applications.
This section discusses the GSM Circuit Switched (CSD) feature in the test set.
The circuit switched data (CSD) channel capability in the test set allows you to simulate a real-time GSM data transfer between your mobile station and a full network. The test set supports:
After establishing a CSD connection, the connection operates in full-duplex. IP datagrams originating from either the mobile station or the "network" may be transferred over this link.
The RF link is maintained even when there is no data being sent or received and is only terminated when you end the call from either the test set, mobile station, or from an attached PC. The only exception occurs if the test set determines that an error condition has been met. If this occurs, the test set drops the call.
For the duration of the CSD connection, the connection status displays "Connected + Data". For the location of the connection status on the front panel display, see Instrument Status Area .
NOTE |
Various modes and bit rates can be used in CSD connections. There are two possible modes:
Bit rates can be 2400, 4800, 9600 or 14400 bps. The following table illustrates the possible configurations and the support provided by the test set.
The test set provides the mode and bit rate requested by the mobile station, if they are supported. When the mobile station's request is not supported, a warning is generated and the call is dropped.
The test set does not have any control over the mode or bit rate requested by the mobile station. Control for this in the mobile station differs between manufacturers. Possible control methods include configuration options available via the mobile station's user interface or by establishing a dial-up connection with the mobile station and using your PC to send it AT commands. Refer to GSM 7.01 for more information.
The
Operating Mode
must be set to
Active Cell
to use the CSD capability in the test set.
The
Connection Type
must be set to
Auto
to use the CSD capability in the test set.
NOTE |
You can make Bit Error Rate(BER) or Fast Bit Error Rate (FBER) measurements during CSD connections. See GSM Bit Error Measurement for more information.
It may be possible for you to make all the GSM transmitter measurements. If your phone goes into DTX mode and stops transmitting, it is not possible to make GSM transmitter measurements.