I used to do this (pre-ooma) on a panasonic phone by hitting the flash button, waiting for a dial tone, then dialing person B's number, then pressing the flash button again.
When I tried it on a panasonic phone (differerent model) I pressed flash, got a dial tone, dialed the number, then I get a fast busy or somesuch.
question is, how do you do a conference call with ooma? thanks
Here is the way using double flash on regular phone: /viewtopic.php?t=14490#p101044
You have to get a feel on how to do this. I described it as slow double click: /viewtopic.php?t=14642#p102068