Changdexun 208M program-controlled telephone switchboard 2 in 8 out 2 external 8 ext 2 drag 8 4 in 16 out 4 external 16 ext Group internal telephone switchboard Cable telephone switchboard Cable telephone Switchboard Cable telephone Switchboard Cable telephone Switchboard Cable telephone Switchboard Cable telephone switchboard Cable telephone switchboard Cable telephone switchboard Cable telephone switchboard Cable telephone switchboard Cable telephone switchboard