As a ISDN subscriber ,In the use of the conference call feature, ISDN subscriber can call in other subscriber one by one ,but always only can tall with the last one ,can not enter the conference call
Second, ISDN subscriber in the last convened a user, must choose ADD button, and then hang up, and then choose “conference” button then meeting will begin. This is different from PSTN subscriber
There are two different when ISDN subscriber and PSTN subscriber use the conference call function
First, ISDN subscriber use the conference call function must also have CALL HOLD functions, and PSTN subscriber do not have this requirement. Because the PSTN subscriber through the FLASH HOOK detect to switch the service , But the ISDN subscriber must use CALL HOLD ,then can use ADD function to call in other subscriber.
Open CALL HOLD feature when using ISDN conference function