Go to the telephone (extension 15), slide the T/P switch toward you, touch a line button (note red lights), touch the line button again until the desired code appears:
Red "on" = ring
Red flashing = delayed ring
Red "off" = no ring (for that line).
Do the same for each line on that extension.
Tom Daugirdas,
President
STCG, Inc.
stcg.com