[. . . ] Version 7. 1 LS-U Line Sensor for the TransTel ML500 System The TransTel Version 7. 1 LS-U Line Sensor offers several unique features when a Telco line is connected to the RJ11 Jack marked TELCO at the rear panel of the ML500 chassis. [. . . ] In the telco mode of operation, it is possible to access the cellular mode by depressing the CELLULAR MODE button on the front panel of the transceiver module. The Line Sensor module consists of a separate board. However, prior to removal of the transceiver module, turn off the power supply and disconnect antenna and telephone cabling at the rear of the of the chassis. In addition, two captive black retaining screws (one in the extraction handle and one at the top of the module front panel) must be loosened. Exercise great care when extracting a transceiver module and avoid any damage to the components of the module. Two switches (SW1 and SW2 on the left upper edge of the Line Sensor board) control settings for closure of the dry contacts on the rear panel of the chassis. Switch settings from 0 through 9 result in the following actions: SWITCH SETTINGS SW2 (left switch) Duration in Increments of 0 or 2n-1 Hours 0 n=1 through 8: 1, 2, 4, 8, 16, 32, 64, or 128 hrs. n=9: indefinite number of hours or until ALARM RESET is pressed; (factory default). SW1 (right switch) Alarm Activation after n Minutes Any setting 0 (factory default) Switch settings 1 to 9 (n=1, 2, 4 , 8 , 16 , 32, 64 , 128 , or 255 minutes delay) ACTION IF TELCO LINE VOLTAGE IS LOST ACTION IF TELCO DIAL TONE IS LOST No alarm contact closure Red ALARM LED on immediately for duration set with SW2. [. . . ] The contacts open automatically (red ALARM LED off) when signal is again acquired or the fault condition has been corrected. 2. All rights reserved. [. . . ]