Talkswitch DESKTOP PHONE SYSTEM User Manual page 84

When would you use double flash?
1. If TalkSwitch is to connected to any other system/service that uses 'Flash' to
activate its features (e.g. a Key Telephone System, PBX, or telephone line
with the Centrex service from your phone company).
2. If you are using any of your local telephone company services that are
activated with 'Flash' (e.g. Call Waiting, 3-Way Calling/Conference, etc.).
What does Single and Double Flash do?
TalkSwitch and the above-mentioned systems/services use 'Flash' to activate
their calling features. TalkSwitch therefore needs a way to tell which (or whose)
features you want to access when you press the 'Flash' button.
Using a 'Single Flash': places the caller on hold. (The Flash is not passed to
the CO line, solving problems associated with Flash causing a hang-up at
some COs.)
Using a 'Double Flash': first Flash places the caller on hold, and the second
Flash (if pressed within 2 seconds) tells TalkSwitch to pass a Flash to the CO
line to activate the CO or PBX intended feature.
Appendices 85