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Emergency Control Room equipment is intended to provide communication between an Emergency Controller and Driver/Guard, using the 4-Wire Omni bus lines which are terminated on Emergency sockets along the track side. By plugging a portable telephone to the emergency socket Driver/Guard can speak to the Emergency Controller.
It consists of a 2 way speech amplifier circuit along with speech combining facility to monitor the speech on both the Emergency and Train Control circuits. The equipment is housed in a console with a handset and loudspeaker arrangement. A volume control is provided to adjust the incoming speech to the desired level. Two separate terminal blocks are provided to terminate the Emergency and Train Control circuits on the back panel of the equipment. By default the equipment gets connected to the Emergency - Trans and Receive lines. The voice can be heard on the loudspeaker as well as the handset. Whenever the PTT switch is pressed the loudspeaker gets disconnected and the incoming speech can be heard only in the handset.
A transfer key switch on the console helps to connect the equipment to the Train Communication Lines in addition to the Emergency Control Lines. When the transfer key is turned ON the speech from the emergency lines gets transferred to the Train Communication Lines and the Train Controller can communicate with the Emergency Telephone connected to the EC socket. Simultaneously the Emergency Controller can monitor the speech of both the Train controller and the Emergency telephone on the loud speaker. During the transfer mode the handset of the Emergency Controller is disabled to avoid confusion. At the end of the conversation the transfer key can be set back to the normal position.
| Tummala Product Code: | TEL/ECRE/99 |
| Power supply voltage: | 12 Volts DC ± 10% |
| Max Current Drain: | 350 mA |
Microphone Amplifier:
| Microphone amplifier Output: | 0 dB |
| Frequency response: | ±3 dB (300Hz to 3400Hz) |
| 50Hz Hum rejection: | > 35dB |
| Gain: | +10dB to -12dB |
| Max undistorted O/P: | > +6dB |
| Frequency response: | ± 3dB (300Hz to 3400Hz) |
| 50Hz Hum rejection: | > 35dB |
| Input Impedance: | 1120 Ω ± 10% |