712 BELL SYSTEM TECHNICAL JOURNAL 



circuit is monitored by means of an amplifier and loud speaker bridged 

 across the circuit through a high impedance coil. This, of course, indi- 

 cates to the attendant the general status of each connection as to trans- 

 mission in both directions. Monitoring by means of a headset is also 

 available and is usually resorted to in those instances where conditions 

 require close attention to the adjustment of the apparatus to insure a 

 satisfactory connection. 



When a call originates on land, the toll operator connects the land 

 line from the shore subscriber to the radio circuit, designated "Harbor," 

 by means of a regular toll cord circuit. This operation, which requires 

 the insertion of a plug in the jack of the radio circuit, automatically 

 starts the transmitter at Point Edwards. It also indicates to the radio 

 attendant by means of an alarm that a connection is being made and 

 that his attention is required to ascertain whether any adjustments 

 under his control are necessary for proper operation of the circuit. The 

 switchboard operator then rings with a 1000-cycle signal which registers 

 as an attention call to all ships which have their receivers operating. 

 Selective ringing is available but requires that ships as well as station 

 be properly equipped. The particular vessel to which a connection is 

 to be made is called by name and station letter. This ship then starts 

 its transmitter and reports and the two-way connection is established. 



On calls originating from a ship, the boat's transmitter is energized 

 and its carrier operates the codan circuit associated with the land 

 station receiver. An auxiliary circuit actuated by the codan functions 

 to signal the Seattle long distance operator by means of the regular toll 

 line lamp signal. It also signals the radio attendant to stand by in the 

 manner described above. The switchboard operator in responding to 

 the signal inserts the answering plug of a cord circuit in the "Harbor" 

 jack which energizes the land transmitter. Two-way telephone con- 

 tact is then established with the ship, and from this point on the regular 

 traffic operating procedure is followed in connecting the ship with the 

 desired telephone station. 



