Using The Ts-850I/Ts-860I With A Traditional Phone Line - Talkswitch TS-860i User Manual

Using the TS-850i/TS-860i with a traditional phone line

When connected to the traditional telephone network (PSTN) or to a TalkSwitch
system as an analog extension, FLASH is engaged by pressing the R# key on a
TS-850i or the key on the TS-860i. The key MUST be held for approximately
2 seconds until you connect to the other caller (call waiting) or receive dial tone
to initiate a calling feature.
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