The following is only applicable to GPSL1L2 channels:
(1) FORCEGPSL2CODE AUTO: - if the satellite is L2C capable, the code type is set to L2C. Otherwise, it is set to P(Y) - if the satellite configuration is not yet known, the code type is set to L2C first. If it is unsuccessful in a limited time period, it will switch to P(Y). This may also timeout. The channel will continuously switch between the two until one is tracked.
(2) FORCEGPSL2CODE DEFAULT: If the Primary channel is configured to AUTO (this is the normal setting means the ASSIGN command hasnt been used on the L1 channel to change its state from anything but AUTO) - the channel will be set to L2C or P(Y) following the same procedure as in (1) above. Otherwise - the channel will be set to P(Y). This is determined by the model loaded on the receiver. Currently, all of the models have the default P(Y). This may change in the future as new models are created.
(3) FORCEGPSL2CODE C: - all secondary channels (in this case, all L2 channels) will be set to L2C. Any channels tracking P(Y) only satellites will not be able to track L2 in this case.