One of the main responsibilities of Firstco recently was to test and commission the telephone and public address / voice alarm systems within the new T5 rail station and tunnels.
The phone systems there consist of over 100 analogue telephone lines. These serve general-purpose telephones and lift intercom and passenger help points, among other devises. The public address / voice alarm system provided both passenger information announcements and voice evacuation message in the case of a fire alarm.
One day Firstco’s engineers will be tracking down faults on the speaker lines; the next they will be completing the final drawing showing the connections of the phones in one of the escape shafts in the tunnel.