| Options | Description |
| Idle Mode | Used to select transmission of the All Marks (or 1s) of the Data Mode Idle sequence for all modes. Options are Disable and Enable. |
| Tx Condition | Used to select transmission of the 56k CSU Control Mode Idle sequence. Options are Normal and Idle. Default = Normal. |
| Clock Source | Sets the clocking source to External and Internal clock. Default = External. |
| Out of Service Tx | Used to select transmission of the Out Of Service sequence for the DDS-PRI mode, or transmission of the Abnormal Station Code sequence for the DDS-SC mode. Options are Disable and Enable. |
| Zero Suppression | Enables or disables transmit zero suppression for DDS-PRI mode, or the transmission of all zeros for DDS-SC mode. Options are On and Off. |
| Loopback | Used to force the CSU to be in loopback mode. Options are Disable and Enable. |