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BT TSX50 (Mitel SX50) Telephone System


TSX50The TSX50 is an integrated communications system which uses an innovative modular design. Up to 10 peripheral circuit cards can be plugged in or taken out without upsetting the system. This allows easy system expansion, fault finding and card replacement. The TSX50 is a compact digital electronic system using stored program control and advanced digital architecture. TSX50 inside view

The TSX 50 can simultaneously use tone, pulse dial or TX14 feature phones. It can cater for up to 160 extensions, 32 exchange lines (trunks), 24 private circuits and has its own console. It has features such as call information logging, automatic route selection, extension metering, direct inward access, direct outward dialling, emergency switching, pick-up groups, baby monitoring, and remote access. 

TSX50 side viewThe TSX50 was first launched in June 1986 with the version UK1 which had G3543/02 software. In July 1989 the UK2 version was released with G3543/03 software. The final version UK3 was released in April 1990 with G3546/01 software. See the table below which explains the differences. The TSX50 had two types of power supply. Earlier versions had the 1A power supply fitted which had an output of 140W, whilst later versions had the higher rated 2A with an output of 225W. See below for the maximum capacity for each type.  


System Capacity
Hardware PSU 1A/G3543 PSU 2A/G3546
MF4 Receivers 5 5
Extensions 80 (5 cards) 160 (10 cards)
TX14's 32 (4 cards) 32 (4 cards)
Operator's console 1 1
Exchange Lines 24 (3 cards) 32 (4 cards)
Mothercards (universal)  4 6
DC5A Private Circuits 8 12
AC15A Private Circuits 8 24
Peripheral card slots 10 10
Trunk Groups 6 10
Trunks per group 24 32

Key differences between generic software G3543 & G3546
Feature G3543 G3546
Abbreviated dialling 60 90/500
Abb. dials saved with data dump no yes
Account Codes no yes
Automatic Route Selection (ARS) no yes
Baby Monitor no yes
Behind PBX working no yes
Conflict dialling no yes
DISA code 159 000
Discriminatory barring yes no (use ARS)
Priority dial 0 no yes
Private Circuit default COS 0 1 (no COS 0)
Reminder calls can be set by extension no yes
Remote maintenance no yes
Trunks default COS 0 1 (no COS 0)
TX14 advisory messages no yes
TX14 name program/display no yes
TX14 console no yes

List of TSX50 System Function Codes & Maintenance Function Codes

TSX50 Peripheral Circuit Cards, Console & Feature Phone

4 Trunk Card 8 Trunk Card DID Card
LS/GS Trunk Card
4 Exchange Line Card
LS/GS Trunk Card
8 Exchange Line Card
DID Trunk Card
Direct Inward Dialling Card
Pt.No: 9104-030-025 Pt.No: 9104-030-000 Pt.No: 9104-032-002
Item Code: 375103 Item Code: 375104

8 Extension Card 16 Extension Card COV (TX14) Card
ONS Line Card
8 Extension Card
ONS Line Card
16 Extension Card
COV Line Card
8x TX14 Extension Card
Pt.No: 9104-020-002 Pt.No: 9104-020-000 Pt.No: 9104-021-000
Item Code: 375105 Item Code: 375106 Item Code: 375107

SSDC5 Module Universal Card
E&M Trunk
SSDC5A Module
Universal Card
Module Mother Card
Control Card 2A
Pt.No: 9104-041-000 Pt.No: 9104-040-000 9104-010-300
Item Code: 375113 Item Code: 375112 Item Code: 375545

RMATS Module Musc on Hold/Pager Module
Remote MTCE Module
Music on Hold Module
Generic Firmware Module
Pt.No: 9104-044-300 Pt.No: 9104-042-002 Pt.No: 9104-011-300
Item Code: 375543 Item Code: 375432 Item Code: 375535
  Not required on G3546 versions  

Power Supply Unit 1A Power Supply Unit 2A  
Pt.No: 9104-000-000 Pt.No: 9104-000-001  
Item Code: 375124 Item Code: 375125  

TSX50 Console tx14.jpg (35663 bytes)  
TSX50 Console TX14 Feature Phone  
Pt.No: 9104-060-002  
Item Code: 375127  

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