Number of minutes for which a write session is active on the equipment. When the value of this variable is 0, the equipment is not locked. When a SNMP manager (iONOSANMSupervisor and Operator) start a write session, tLock can be set to a value by the manager (up to 30 minutes, so it has time to configure the equipment). Each time an action is done under the equipment tLock is set again to its value. tLock is a decremental counter; when the value of tLock return to 0, the write session is ended and the equipment is unlocked. The SNMP manager can choose to unlock the equipment by setting the value of tLock to 0 before it reach this value itself.