Page 1 of 26 / Effective from 24/10/2006 / RDSO/SPN/TC/64/2006 / Rev. 0





Revision 0.0

Number of Pages: 26




RDSO/SPN/TC/64/2006 / Revision
Title of Document
RDSO Specification for Display and Public Announcement System in the Coaches of Trains
Shri Anil Kumar Mishra
Director/ Telecom-II/ RDSO
Approved by
Shri M. Alam
Executive Director/ Telecom/ RDSO
This document specifies technical specification of Display and Public Announcement System in the Coaches of Trains.









Director/ Telecom-II /






Executive Director/ Telecom








Version / Chapter/ Annexure / Revision / Effective Month/Year


/ - / FIRST ISSUE / October, 2006


Sr. No.




Page No.


/ Scope /



/ System Description /



/ System Specifications /



/ Software Requirement /



/ Power Supply /



/ Tests & Requirements /



/ Test Procedure /



/ Quality Assurance /



/ Marking & Packing /




Information to be supplied by the Manufacturer




/ Information to be supplied by the Purchaser /



/ Training /



/ Diagram 1 /


Draft Specification for Display and Public Announcement System in the Coaches of Trains

Draft Specification No. RDSO/SPN/TC/64/2006


This document covers the technical requirements of display and public announcement system in the Coaches of trains using GPS modules and GSM/GPRS modems.


Draft specification RDSO/ SPN/ TC/ 64/2006, Rev.0 has been prepared by RDSO, Lucknow as per Railway Board letter No. 2004/Tele/Plg.2/IRPM Vol. I dated 13/12/2005.


RDSO/ SPN specification is issued as draft specification. This specification is circulated to customers/ Railways and field inspection units for comments.

In the absence of IRS specification, procurement may be made as per RDSO/ SPN specification.

This specification requires the reference to the following specifications:
IRS: S23 / Electrical signaling and interlocking equipment
RDSO/SPN/144 / The Safety and reliability requirement of electronic signaling equipment
IS:9000 / Basic environmental testing procedures for electronic and electrical items

Wherever, reference to any specifications appears in this document, it shall be taken as a reference to the latest version of that specification unless the year of issue of the specification is specifically stated.

For the purpose of this specification, the terminology given in IRS: S23 and RDSO/SPN/144 shall apply.


The specification of Display and Public Announcement in the Coaches of the trains covers technical requirement of GPS and GSM/GPRS based system for making public announcementindifferent coaches of running trains and displaying train information through LED & LCD based display boards.


Schematic diagram of GPS and GSM/GPRS based Display and Public Announcement Systemin the Coaches of trainsis shown in diagram -1. The system shall consistof PC based Central Control Unit, Data Communication Router, GSM/GPRS modemslocated in Divisional Control Office and PC based announcement system, Display Boards alongwith Coach Processor Unit(having built in GSM/GPRS modem & GPS module) to be provided inside coaches of train.

Central Control Unit (CCU)located in divisionalcontrol office can acceptdata through manually or from train charting server. CCUis connected with Data Communication Router through serial communication. The CCU is equipped with the announcement and display boards driving software with all the necessary features for making announcement and displaying train information & general information inside coaches of trains. Using GSM/GPRS modem and data communication router, prerecorded announcement and messages can be announced and displayed inside running trains.

Two display boards with one number of Coach Processor Unit having GSM/GPRS modem & GPS module are to be provided for each coach to avoid data communication wiring from one coach to another coach.Each GSM/GPRS modemshould have its own identity (mobile SIM card)which shall helpin addressing the Coach Processor Units installed inside coaches of train for driving display boards and PC based announcement systeminstalled in announcer cabin of train where PA system already exists. LCD modules are to be provided in compartmentalized coaches like cabins and coupes of 1st AC.

When data is keyed to CCU either through manual entry or through train charting server, itshall be transmitted to either PC based announcement system or display boards provided inside train through GSM/GPRS modem via Data Communication Router from PC. On receipt of the data through GSM/GPRS modemby Coach Processor Unit of coach, it shall givean output to display boards for display. Similarly on the receipt of data through GSM/GPRS modem, the PC based announcement system shall be able to announce the messages through existing PA system. It shall be possible to display the information in several special effectswhichcan also be configured from the control room. It shall also be possible to display information about location of train, approaching station etc. with the help of GPS module of Coach Processor Unit.

Announcement inside coaches of train shall be centralized from the announcement cabin as existing in Rajdhani & Shatabdi trains to make common announcement and play music etc. in all coaches of train. For this, coach to coach wiring along with PA system consisting of amplifier, speakers etc. are to be provided similar to Rajdhani & Shatabdi trains. Centralized control of PA system can be by the nominated staff of the train.


3.1Hardware Requirements:The system shall consist of:

3.2Central Control Unit :(CCU)

3.2.1Central Control Unitshall take the data either manually or from train charting server. It shall send the data to PC based announcement system and display board in running train through data communication router.

3.2.2The CCU shall comprise standard PC of reputed brand having minimum configuration as mentioned below:

a)Pentium – IV or equivalent processor, 2GHz or higher

b)512 MB SD RAM

c)80 GB HDD

d)CD writer

e)17” Color LCD Monitor

f)101 Key Board

g)Optical USB Mouse

h)At least 1 Parallel Port 2 Serial Ports

i)UPS with minimum ONE hour battery backup

j)WINDOWS XP professional

k)Ethernet card

l)Antivirus software

3.3Data Communication Router:

3.3.1The data communication router shall be a multi-port serial communication router to which the GSM/GPRS modem shall be interfaced for information transfer.

3.3.2Data communication router shall receive data from CCU and shall routeto the respective systems in running trains.

3.3.3It shall be based on minimum 8 bit processor.

3.3.4Communication lines shall be optically isolated.

3.3.5The portsshall be able to work for data send and receive both and in full duplex mode.

3.3.6Proper communication protocols shall be provided to establish error free communication between the port and the corresponding system interfaced with that port.

3.3.7.Necessary diagnostic routines shall be provided to the operator with the help of which he shall be able to avail the information regarding the faulty ports so that the necessary action can be taken to rectify the same.

3.3.8In case of failure of any particular port, the spare port shall be used immediately and the system shall start functioning with minimum down time.

3.4P.C BasedAnnouncement System:

3.4.1The system shall be located in the ‘AnnouncementCabin’ of trains.

3.4.2The system shall receive the data through GSM/GPRS modem from central control unit and announce the received message with the help of prerecorded digital voice data on existing PA system.

3.4.3There shall be provision for making manual announcement.

3.4.4The software shall have provision to enter the messages manually and announce the same with pre recorded digital voice data.

3.4.5This shall comprise standard PC of reputed brand having minimum configuration as mention in clause 3.2.2 and meeting the features pf PC based announcement system as mentioned in RDSO Specification No. RDSO/SPN/TC/61/2006, Revision 1.0.

3.4.6System shall work on either 110V AC or DC supply available in coach of train as specified by purchaser.

3.5Coach Processor Unit:

3.5.1A Coach Processor Unit (CPU) shall be a microprocessor/ microcontroller based System.

3.5.2A CPU shall have an in-built GSM / GPRS modem and a GPS module interface to the Microcontroller/ Microprocessor.

3.5.3The CPU shall work on either 110V AC or DC supply available in coach of train as specified by purchaser.In built SMPS power supply shall be provided for CPU, GSM/GPRS modem and GPS module.

3.5.4The CPU shall have an on-board RTCand at least 1MB non-volatile Flash Memory that should store the data pertaining to the operation of the system.

3.5.5The CPU shall have a 16X2 alphanumeric display for local monitoring.

3.5.6The CPU shall have an onboard optically isolated interface for communication with display boards and LCD modules. One CPU shall be able to drive at least two numbers of display boards & 8 numbers ofLCDmodules installed inside a coach of train.

3.5.7The CPU shall receive thedata from the CCU through data communication router using its GSM/GPRS modem and shall update information to be displayed.

3.5.8The CPU shall also have one serial port interface for programming the unit with a data needed for the operation of the system.Also there shall be provision to update the data in flash memory through GSM/GPRS modem.

3.5.9The CPU shall perform a validation check on the data received and process the valid data.

3.5.10The CPU shall use the signal from the GPS module and automatically calculate the distance to the next approaching station, speed of the train and the current time etc. Using this data, the CPU shall compile the messages for the display boards. The CPU shall also generate relevant messages/ slogans as defined by user.

3.5.11Each coach shall have its own Coach Processor Unit consisting of a dedicated GSM/GPRS modem and GPS module. All type of messages to be displayed shall be generated independently in order to avoid wiring from coach to coach.


3.6.1GSM/GPRS modem shall be integrated in the Coach Processor Unit. It shall derive the power supply form SMPS power supply of CPU.

3.6.2It shall be of standard make and shall have the following minimum specifications.

a).Dual Band GSM 900/1800 (1900) Phase 2/2+ Modem

b). DataRate: 300---14400 BPS, transparent/nontransparent,

V.21,V.22 bis, V.26 ter, V.32, V.34, V.110

c).Interfaces: Serial & removable SIM Card Holder

d).Storage temperature -200C to +700C

e).Small rugged Antenna

3.7GPS Module:

3.7.1The GPS module shall be integrated in the Coach Processor Unit and interfaced with an active antenna to be fixed on the top of the coach with a clear view of the sky.

3.7.2GPS module shall derive power from the SMPS power supply of CPU.

3.7.3It shall be of standard make and shall have the following minimum specifications.

a).12/16 Channel GPS Receiver with built in LNA

b).External Active Magnetic Antenna

c).NMEA 0183 compatible Output

3.8LED Based Display Board:

3.8.1Display boards shall be provided inside coaches of train to display train information. LED Based Display Board shall be SMD type.

3.8.2Display boards shall be designed with minimum 8 bitprocessor.

3.8.3Display boards shall be located at both entrances of a coach. The exact location is to be indicated by the purchaser.

3.8.4There shall be provision to display the status like late running, coach composition,general messages etc.

3.8.5The display boards of various types shall be dust proof, water proof and vibration proof as per IP 54.

3.8.6Display on the board shall be flicker free.

3.8.7The display on a board shall be immune from the effect of 25 KV traction line or electro magnetic induction or any other electro-static induction.

3.8.8 The information on display boards shall be displayed in turn in English, Hindi and if so required by the purchaser in the regional language. Each display shall last for specific period of up to 60 seconds which may be adjustable.

3.8.9Every display board shall be covered with a transparent layer of acrylic sheet of thickness minimum 3mm in order to give good visibility with protection against dust.

3.8.10 LEDs with equal fringe and uniform intensity are to be used to ensure that the information to be displayed is with excellent contrast so that no black patches are visible on the display screen.

3.8.11These display boards shall be constructed using PCB module of 16X48 matrix. The mechanical mounting of these modules shall be such that easy replacement of module PCB is possible in case of repair. Such replacement shall not call for removing any other PCBs.

3.8.12The construction of the whole unit of display boardshall be modular, such that any module (i.e. PCB, connector, cable, power supply unit etc.) can be easily removed when defective and a fresh module is fixed to make the system functional again. Wiring between different modules shall be done with the help of male/female type of connectors. There should not be any requirement of rewiring, re-soldering/de-soldering or opening and reconnections of wiring etc. during the maintenance, unless there is damage to the wiring.

3.8.13The relevant ICs for the display board shall preferably be of surface mounted device (SMD) to ensure high reliability.

3.8.14There should be no changes in electronics to add extra modules to the display boards in addition to the numbers mentioned in the specifications.

3.8.15 Display Boards shall be capable of working in an ambient temperature range of -100 C to +700 C and relative humidity up to 95% at ambient temperature range of 400 C without any degradation.

3.8.16There should be in built power supply to work directly either on 110V AC or 110V DC derived from coach supply with short circuit protection with properly rated fuse at its input. High voltage protection shall also be provided.

3.8.17The display board shall communicate with Coach Processor Unit through optically isolated communication interface.

3.8.18The display boards shall not display any garbage until the required information is placed on them from the Coach Processor Unit. All the embedded boards with processor shall have watchdog circuit, which should reset the processor in case the processor goes haywire due to any external disturbance caused by high voltage traction etc.

3.8.19Material for the printed circuit board shall be copper clad glass epoxy of grade FR-4 or equivalent. The display PCB thickness shall be at least 2.4mm. The thickness for other PCBs shall be at least 1.6 mm.

3.8.20 CONFORMAL COATINGS: Assembled and tested printed boards shall be given a conformal coating to enable them for functioning under adverse environmental conditions. The coating material should be properly chosen to protect the assembly from the following hazards.


b)Dust and dirt;

c)Airborne contaminants like smoke and chemical vapors;

d)Conducting particles like metal clips and filings;

e)Accidental short circuit by dropped tools, fasteners etc.;

f)Abrasion damage and

g)Vibration and shock ( to a certain extent )

3.8.21The solder masks shall be applied on the solder side and component side of the card.

3.8.22Following description shall be etched on the component side of the PCB:

a)Component outline in the proximity of the component;

b)Manufacturer’s name.

c)PCB name.

d)Part number.

3.8.23Following description shall be engraved on the PCB:

a)The manufacturing serial number.

b)Month and year of manufacture.

3.8.24LED matrix of 16x32should be designed such that the maximum multiplexing should be 8 and the refreshing time should not cross 20milli seconds.

3.8.25Suitable rating (100% excess to the maximum load) of Power cable with standard color coding should be used.

3.8.26Preferably 4 pairs (2pairs for working and 2pairs for standby) of suitable shielded Communication Cable with color coding should be provided.

3.9Specification of LED (SMD Type):

3.9.1Super bright RED or ORANGE or GREEN color SMD LEDs of uniform intensity are to be used for longer visibility in various type display boards. Colour of LED is to be specified by Railways. The intensity of the illumination should be such that it shall be possible to read the information clearly from a distance of minimum 25 meters. This visibility is to be checked and ensured for that part / spot of indicator which has maximum intensity of ambient light.

3.9.2LED Specification:

Diffused/ Colorless clear Red or Orange or Green color LEDs (Light Emitting Diodes) of Surface Mounting Devices (SMD) types should meet following parameters.

SN / Parameters / Red SMD LEDs / Orange SMD LEDs / Green SMD LEDs
a. / LED Type / Diffused/ Colorless clear / Diffused/ Colorless clear / Diffused/ Colorless clear
b. / Color / Red / Orange / Green
c. / Wave Length / 626+/-10nm / 605+/- 10nm / 525+/-10nm
d. / Directivity ( 50% IV (in mcd) / 1100 (Minimum) / 1100 (Minimum) / 1100 (Minimum)
e. / Luminous Intensity @ 20mA biased current / 100mcd / 100mcd / 150mcd
f. / Operating Temperature / - 300C to + 850C / - 300C to + 850C / - 300C to + 850C
g. / Make / Avago or Nichia or OSRAM / Avago or Nichia or OSRAM / Avago or Nichia or OSRAM

3.9.3Viewing Angle of LED: the LED under test as shown in the above set up in a dark room. the LED such that the rated current flows in the LED under test. the distance between the tip of the LED and Chroma meter or Spectrometer diffuser to 10 cm exactly. the Chroma meter or Spectrometer to measure the intensity in Lux in the position indicated in the set up. Rotate the LED so that the chroma meter or Spectrometer records maximum Lux. Record this value and position of LED in degrees. the LED in Horizontal (X direction) to a point, at which the Lux reading is half of the value that was observed in the clause Record the position of LED in Degrees. Calculate the degrees the LED was rotated from the maximum intensity value to half intensity value. Record this value is as Thetaa. Similarly rotate the LED in opposite direction from the maximum intensity value and mark the point where the Lux value observed is half the value to the one observed in the center. Calculate the rotation in degrees from maximum Lux value and record this value as Thetab.

3.9.4Calculation of dispersion Angle:

Dispersion Angle= Thetaa + Thetab

3.9.5 Intensity of LED in mcd: