TILT UP row of teletypes to operators at work checking messages at Communications Central, central analysis office. TRAVELLING SHOT along row of teletypes. Shot of hands threading tape through machine from behind machine. CU of punch tape going through machine. MCS of punch tape coming out of machine. CU of teletype message being received. ECU of coded message being typed on incoming communication. Shot of facsimile machine in operation, operator checking other machines.