tx p line 50 p now considered active the switch 26 of the protection module 20 passes signals from the corresponding receiving rx p line 51 p to the amplifier module 13 thus the module 13 is not monitoring the working rx w line 51 w to determine its return to operating condition the correct line restart cannot be performed for the corresponding transmitting tx w line 50 w the apr procedures cannot be performed to avoid these problems the present invention provides for the close interoperation of safety measures with protection measures the protection module 20 is modified so that the switches 23 w 23 p are replaced by voas 33 w 33 p and the module 39 s operations are changed with a control unit 45 u2032 the modified protection module is labeled 20 u2032 with the same elements as the module 20 except the switches 23 w 23 p and the control unit 45 u2032 the connections of the amplifier module 13 and protection module 20 u2032 are shown in fig4 and unchanged from those of fig3 in this embodiment of the present invention safety and protection measures are installed in the protection module 20 u2032 besides being able to control the output power of the signals leaving the transmitting ports 49 w and 49 p independently the variable optical attenuators 33 w and 33 p are used to control the amplifier output in accordance with safety procedures in the following description the avs automatic voa shutdown command status for the module 20 u2032 corresponds to as als automatic laser shutdown command status used.