This read-write TimeInterval, ranging from 0 to 3,600,000, controls how long the BER test signal insertion on the selected line or lines will run. An admin sets a bounded value here so a test that necessarily disrupts live traffic on the tested line automatically ends rather than being forgotten and left running. For example, choosing a fixed duration like 60000 lets the BER test complete and the line return to service automatically, whereas leaving it at 0 would require someone to remember to stop it manually.