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DFR - Diagrams in PDF Form

Cinderford Exchange etc

This is a 22 line 4000 type exchange that could be used at the far north of any extension to the railway. Construction has started. The equipment is being designed so that the exchange will be very versatile. It will work as a stand alone unit or it could be integrated into the DFR linked numbering scheme. All outgoing junction calls will be regenerated as the junction cable length will be rather long.

Final Selectors

Line Finders

S & Z Generator

Line Circuits

90 Exchange Phone Line

99 Test Line

I/C Junctions from Dependent Exchange

Alarms

Fuse Layout

Rack Strips Connection Layout

Ringer 2A Connections

Ringer Start Circuit

Power Unit Arrangements

Selector Hunter Busy Tone Circuit


Lydney Junction Exchange etc.

This is a simple uniselector 22 line exchange. The uniselector line finder extends a caller to Norchard and the Norchard first selector provides dial tone. Any one dialling a 6 is connected to a junction incoming to Lydney Junction and the two final digits are used to position a uniselector onto the called number's line circuit. Local calls on the Lydney Junction exchange are therefore connected via junctions to and from Norchard. This was known as trombone working.

Exchange Line Circuits

Line Finders

Final Selectors

Test Number

S & Z Generator

Low Volt Alarm & Clock Pulse Reception

Ringer Start & Ring Distribution

MDF Terminations

Power Unit

Concentrator Line Circuits & Operator Circuit

Concentrator Timer Circuit


Norchard Exchange etc.

The exchange is basically a standard UAX13, however many locally designed selectors and relay sets have been added for various purposes over the years and these diagrams are listed below. The standard UAX13 diagrams are not shown here.

Clock Pulse Generator Relay Set

Aux & Distant Clock Drivers (& SpareLevel NUT)

Ring Back Relay Set

Outgoing Junction Relay Set

Bothway Junction Relay Set

Final Selector Busying (Rack A1)

Final Selector Busying (Rack A2)

Junction Call Count Meters

Outgoing Junctions Distributor

Incoming Junction 4000 Type Selector

Level 0 Single Digit Final Selector

Demo Direct Exchange Line 4000 Type Selector

Concentrator Line Circuits

Concentrator Operators Circuit

Concentrator Timer

Concentrator Tone Generator

Concentrator Ringing Converter

Concentrator Head Tester Keys

Power Supply Arrangements

PW Tele to Tele Circuit


Parkend Exchange etc.

The exchange has been constructed mostly from PABX4 equipment, however many locally designed selectors and relay sets have been added for various purposes over the years and these diagrams are listed below.

Test Selector

Test Selector Access

Clock Pulse Reception

Incoming Final Selector

Local Final Selector

Final Selector Call Distributor

Line Circuits & First Selector

Incoming Selector (Issue C)

Incoming Selector (Issue D)

S & Z Generator

Ring Back

Spare Level NUT

Fuse Layouts

Multi Level Auto-Auto R/S with Regenerator

Both Way Auto-Auto Relay Set

Rectifier Diagram

Power Plant Connections


Parkend North Exchange etc.

This 22 line uniselector exchange is not yet in service. It is complete and waiting installation in Parkend Signal Box. It has been designed specifically to allow long lines to be connected to it and so will be available to service any lines going north from Parkend as the railway extends. It is very similar in circuit design to Lydney Junction Exchange but has been physically constructed somewhat differently. All outgoing calls will be made via first selectors in Parkend exchange. Incoming calls will arrive via junctions from both Norchard and Parkend.

Exchange Line Circuits

Line Finder & O/G Auto-Auto Relay Set

S & Z Generator and Allotter

30 Sec Pulse Generator

Final Selector

Test Number

NU Tone for Spare Numbers

Low Volt Alarm

Alarms

Clock Pulse Reception

Ringer Control & Connections

Power Unit

Concentrator Line Circuits

Concentrator Operator's Circuit

Concentrator Timer Circuit

Concentrator Head Circuit

Concentrator Operator Phone

Concentrator Type 4 Uniselector Connections


STARS

STARS (Signals and Telecoms Alarm Reception System) collects alarms from around the railway and directs them back to Norchard. Any alarm is first displayed by the appropriate lamp lighting on a simple display at Norchard exchange. If the alarm persists for more than six minutes it then lights a lamp in a key and lamp display in the shop office. The appropriate officer can then be informed of the alarm condition. The system is notable for the way in which up to three alarm locations can be combined to transmit alarm signals over a single wire to Norchard.

STARS Circuit Elements

STARS Reception Relay Set at Norchard

STARS Shop Display Relay Set

STARS Parkend Alarm Relay Set

STARS Lydney Junction Alarm Relay Set

STARS Norchard IDF Termination Strip Connection


NORCHARD PUBLIC ADDRESS EQUIPMENT

The public address equipment is quite complicated as access to the amplifier is required from two microphone positions and from several telephones around the site. These telephones gain access to the amplifier by dialling a Norchard number and by also pressing a button which puts a loop on a control pair. The amplifier is also accessed on a high priority basis by the fire warning equipment to distribute a warning tone, and by a CD player with very low priority to provide background music when required.

Overall circuit diagram 120Kb

PA Circuit Elements 210Kb

IDF Terminations 37Kb

Norchard Speaker Arrangements 38Kb

Music Channel Equipment 87Kb

PA Tele Access R/S U Points 82Kb

PA Audio Switching R/S U Points 84Kb

24V Supply 47Kb

Microphone Connections 139Kb

Common Service Blocks 52Kb


NORCHARD FIRE WARNING EQUIPMENT

The Fire Warning equipment was designed as an interim system until a regular fire alarm system could be installed by our alarm contractor. The equipment is still in use. Essentially, if any one on the Norchard site dials a given number on an internal phone, then the warning system provides a warbling tone over the PA system for one minute. The originator can hang up and dial other numbers while the one minute tone is sounding. The two microphones connected to the PA system have priority over the warbling tone so that instructions can be issued over the PA.

Overall circuit diagram 254Kb

Shop Equipment 36Kb

Terminations on the IDF Local Block 60Kb


NORCHARD CLOCKS

The Clocks at Norchard are controlled by a standard GPO pendulum master clock. A second master is available and can be switched in should there be a difficulty. We have three types of clock in use.

1) the usual 30 second pulse clocks that are connected in series within the main building.
2) clocks that are driven over separate pairs by a 50 volt supply that reverses every 30 seconds.
3) pulse clocks that are remote from the main building and need to be fed via separate pairs with a 30 second pulse.
4) the 30 second pulses are also fed to Parkend and Lydney Junction over the second wire of the alarm/clock pair.

Master clocks and main circuitry

Distant clock drivers circuitry



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Page provided by John Bathgate

This page was last updated on
10th September 2017