Giant Electronics Ltd 2G4DSSL2400 ユーザーズマニュアル

The ‘H’ is displayed too as below, when the internal call is put on hold.

TALK 1:35:50
EXTERNAL CALL H

An incoming call can be transferred or forwarded to the other handset during an ongoing call. The difference is that, when the call
is transferred, the first handset waits for the other to answer before ending the connection, but when the call is forwarded, the first
handset ends its connection immediately.

6.8.1  The Call is Transferred

1) Press the key (the external call is put on hold)

2) Press the number of the required handset or ‘*’ key for all handsets.

1... 4  *
OR
Press the UP/DOWN key to select the desired handset(s) in the menu, then press PHONE or PROG (the external call is put on
hold).

,   

 / 

3) After the other handset has answered, press PHONE, or place your handset in the charge cradle.

6.8.2  The Call is Forwarded

1) Press the key (the external call is put on hold)