# CVPORT System Variable [GstarCAD 2022](Help%20System/GSTARCAD/2022/Index.md) → [System Variables](Help%20System/GSTARCAD/2022/System%20Variables/(System%20Variables).md) → [C](Help%20System/GSTARCAD/2022/System%20Variables/C/(C).md) **Function Description:** The CVPORT system variable is used to change identification code in current viewport. | | | | --- | --- | | Type | Integer | | Saved in | Drawing | | Initial value | 2 | **System Variable Value:** Users can change current viewport by setting the CVPORT system variable, first they should meet the following conditions: 1\. The specified identification code should be one active viewport code. 2\. The cursor has not been locked and it can move to viewport when executing a command. 3\. The Tablet mode has turned off.