Main Switching Unit (MSU)

MSU

• Main switch• Switching• Billing• Subscriber administration• Call processing and routing• POTS, BRI and PRI services

RDLU

• Only access part• Switching in MSU• POTS and BRIs only• Local RDLU works within same exchange area• Long Distance RDLU works in another billing zone

LTG SN

Signaling UnitCCNC

Processor

IBM Compatible

Telephone

Telephone

Fax

PBX

Public switch

DLU

Storage

RDLU

Long Distanceor

Junction Network

Telephone

Telephone

Fax

Switch Components

Local RDLU

MSURDLU

PTC(L) Network

Multi-Exchange Area

Example L/D RDLUs

NTC Cx Gujranwala NTC RDLU Gujrat

PTC(L) Tx Gujrat

4 x E1

2 x E1

PTC(L) Lx Gujrat

PTC Sub

NTC Sub

PTC(L) TX Gujranwala

PTC LX Gujrnawala

PTC Sub

NTC Sub