CONTROL COMMUNICATION EQUIPMENTS FOR OFC USING 2-WIRE TELEPHONES (CCEO)
CCE are set of equipment used for traffic management and infrastructure control for the Railways. They enable quick and hassle-free communication between different sections to make traffic management more efficient and safe.
It is as per RDSO specifications – RDSO/SPN/TC/66/2007
Control office Equipment
Control Room Equipment (CRE)
Test Room Equipment (TRE)
Local Telephone Equipment (LTE)
Multi Telephone Waystation Equipment (MTWE)
Remote Patching Equipment (RPE)
Three Way Amplifier (TWA)
Two-Wire Dialling Control Telephone (TDCT)
- Section Control
- Deputy Control
- Engineering Control, etc.
- Traction Power Control
The CCEO consists of following seven segments:
- 1.Control Rooom equipment
- 2.Test Room equipment
- 3.Local telephone equipment
- 4.Multi Telephone way station equipment
- 5.Remote patching equipment
- 6.Three-way amplifier
- 7.Two-wire dialing control telephone
All these equipment are 19’’ inch rack mountable. CRE,TRE <E are part of Headqurters of control. MTWE is situated at each station.
CRE is desk type with single push button calling arrangement. It has 40 Push Buttons with Page-Shift Push Button, for calling TDCT or Way Station Equipment. This will yield to a calling capacity of minimum 80.It is also provided with 5 Push Buttons or Page-Shift Push Button as Group Buttons for calling a group of TDCT or Way Station Equipment. CRE is having the facility to call individual TDCT, or a group of TDCT, by single push button, directly or following the Page-Shift push button. This action will initiate a ring at the TDCT and provide an audio feedback to the controller. The feedback tone will be ‘positive’ type.
The Test Room Equipment is directly interfaced to the OFC System for the Control Circuit on 4-Wire configuration. Gain settings of ±6 dB is available for DTMF and VF Signals on the trans and receive channel of the equipment. The Test Room staff can call any TDCT or Local Telephone by using the numeric push button for composing the number. It is also possible to initiate a call to a Way Station Equipment.
The Local Telephones Equipment is to cater to 20 Local Telephones. These telephones shall work on a pair and connect on one-to-one basis, in star connection configuration from LTE, using a twisted telecom pair having loop resistance of less than 1200 Ohm. The telephone instrument used as Local Telephone will be a TDCT instrument, identical to What is used with MTWE.
The Local Telephone connected to the LTE has facility to get called by CRE and TRE but has no dialing facility. On picking up the handset, the Local Telephonel is got connected to the control circuit. The CRE has facility to disconnect any particular Local Telephone.
The MTWE shall be directly interfaced to the OFC for the control circuit on 4-wire circuit configuration. Gain settings of ±6 dB shall be available for DTMF and VF signals on the trans and receive channel of the equipment. The VF channel shall provide interface as a ‘digital branching in both direction’ configuration arrangement with a 600 ohms interfacing impedance with a unity input-output level arrangement. A total four numbers of Two-wire Dialling Control Telephones (TDCT) will be connected to the equipment, each on a twisted telecom pair. A feedback tone will be generated by the MTWE whenever a ring to one of its TDCT is received.
The RPE can interconnect (patch) two VF 4-wire channels of 600 ohms impedance to each other. It is possible to interconnect the two channels by a local command (from the RPE panel) or from a remote command (from TRE). The interconnecting path for the two channels will have transformer isolation and active components as well. With this, the channels are remain isolated and also provide impedance isolation between each other. The PRE will provide a unity gain path for the patching channels. The channel patching status should be seen on the PRE panel. The action of patching and unpatching the channel shall be carried out by pressing a push button on the RPE panel, when operated locally.
The equipment can provide a unity gain three way branch amplifier configuration. Wherever more than one MTWE is to be deployed, the TWA can be used as to provide the additional 4- wire branch connection while keeping unity gain and impedance isolation. The TWA is directly interfaced to the OFC for the control circuit on 4-wire circuit configuration and have a 600 ohms. No gain setting will be required for interfacing. The TWA is used as a means to provide connections to additional MTWE and not to branch out the control circuit to open line.