Cursor Color

By default, PC/3270 draws the underline cursor in white. If the background color of the current field is white, the color of the underline cursor automatically switches to black. PC/3270 draws the block and half-block cursors in the same color as the current field, reversing the background and forground colors. This behavior is identical to a 327x terminal.

If you want to change the default cursor color assignment, modify the pcswin.ini file and add the CursorColor value to the Session stanza, as follows:
CursorColor=<red_value> <green_value> <blue_value>
Here, <red_value>, <green_value>, and <blue_value> are integers from 0 to 255 that specify the color intensity for each color primitive respectively. The color values range from 0 0 0 for black to 255 255 255 for white. PC/3270 then draws the underline cursor and the block cursors in this new color, mixing this new color with the existing screen colors using an XORed (exclusive or) operation. The value 0 0 0 (black) is not recommended because XORing 0 0 0 with any existing color results in the existing color, which makes the cursor invisible.
If you select a blinking cursor, it will always be drawn white, mixing the white with the existing screen colors using an XORed operation. You cannot change the cursor color when it is blinking.
Note: Cursor blinking is disabled by default in Windows Terminal Services sessions and under virtualization environments such as Citrix XenDesktop and Citrix XenApp. Refer to the appropriate vendor documentation to enable cursor blinking.