HOUSE TELEPHONE SYSTEMS


House Telephone Systems are just intercom systems.  There is no connection to an exchange line.  Systems were powered originally by batteries, but today small power units have taken their place.  Due to the miniaturisation and lower cost of automatic telephone systems (PABX), HTS/intercom systems are virtually non-existent today.


BT House/Internal Telephone Systems (HTS/ITS) had no connection to the BT Network and were installed as intercom systems within customers premises, typically in large supermarkets. The range comprises:-

HTS No.1 - Press button telephone intercom system with table or wall mounted telephones (similar in appearance to 300 type instruments) with 5, 10 or 15 buttons depending on system size, maximum system size is 15 stations. The telephones are interconnected by multi-pair cabling (12 wire for 5 station systems, 21 wire for 10 or 15 station systems) and locally powered by dry batteries.

HTS No.2 - Press button telephone intercom system with table or wall mounted telephones (similar in appearance to 706 type instruments) with 5, 10 or 15 buttons depending on system size, maximum system size is 16 stations. The telephones are interconnected by multi-pair cabling (21 wire for 6 stations, 24 wire for 11 stations and 41 wire for 16 stations) and powered by a mains Power Unit 53.

ITS No.3 (PROTEUS 24 and 64) - Standard type 'Dial' or 'Press Button' LD signalling telephones connected to a free standing self-contained Central Control Unit (CCU) containing electronic switching and control circuitry. Was marketed under the name of Proteus. The telephones are 2-wire connected to the CCU via twisted pair cabling. Maximum capacities 24 or 64 stations depending on type of backplane and line interface equippage. The system is mains powered by a Power Unit 155A contained within the CCU.


HTS No. 1 was introduced in 1959 and made obsolescent in October 1973. HTS No. 2 was introduced in 1967 and ITS No. 3 in 1982.

It was intended to withdraw all HTS/ITS by September 1992 and all identified customers were contacted by sales groups to encourage change out for a modern system.

HTS/ITS do not have a telephone number and so it has become the practice to issue a 'Private Circuit' number for fault reporting or billing purposes on HTS 1 and 2 systems, ITS No 3 (Proteus) should have been recorded on CSS.

In practice many customers were not aware of these private circuit numbers for reporting faults or even realising that they are BT maintained systems resulting in faults not being reported.

The ITS was manufactured for BT/GPO/Post Office by various companies, only the ITS No.3 CCU was manufactured by BT Fulcrum.
All systems were rented

APPROVAL STATUS
None as ITS systems are not network connected and hence not subject to the Approval scheme.

DOCUMENTATION
M&S Circular 214/91 'Withdrawal of Internal Telephone Systems & Proteus.
HTS No. 1 - Diagrams Q 351,352 & 353. TIs C3M 4000, E5D 7301.
HTS No. 2 - Diagrams Q 361 & 362. TIs C3M 4001, E5D 7302.
ITS No. 3 - Customer Apparatus Guide Notes 'Proteus 24 & 64' (Site documentation supplied with system), TIs C3M 4010 & ESD 7302.

HANDLING PRECAUTIONS
ITS No. 3 CCU contains static sensitive CMOS components, precautions must be taken to prevent static damage.

The above was taken from BT documentation

Description                                                          BT Item Code

HTS No 1:-
Telephone  House   100,  (5  stations    -table model)                  42  1902
Telephone  House   101,  (5  stations    -wall model)                   42  2034
Telephone  House   102,  (10 stations    -table model)                  42  1903
Telephone  House   103,  (10 stations    -wall model)                   42  2035
Telephone  House   104,  (15 stations    -table model)                  42  1904
Telephone  House   105,  (15 stations    -wall model)                   42  2036

HTS No 2:-
Telephone  House   500,  (5  stations    -table model)                  42  0153
Telephone  House   501,  (5  stations    -wall model)                   41  0192
Telephone  House   502,  (10 stations    -table model)                  41  0154
Telephone  House   503,  (10 stations    -wall model)                   41  0155
Telephone  House   504,  (15 stations    -table model)                  41  0156
Telephone  House   505,  (15 stations    -wall model)                   41  0193
Power Unit 53B                                                          31  4065

ITS No 3:-
Proteus Power Unit 155A                                                 43  200#
Proteus Case   246 A                                                    43  201#
Proteus Case   246 B                                                    43  202#
Proteus Card   1A1/FDH 16891 (Red Handle)                               43  203#
Proteus Card   1A1/FDH 16900 (Yellow Handle)                            43  204#
Proteus Card   1A1/FDH 10894 (Blue Handle)                              43  206#
Proteus Card   Common Control PCB                                       43  209#
Fuses 3 Amp,   500 mA, 1 Amp (spares supplied with CCU)
BT Repair Services (Formerly Fulcrum) Item Code numbers.
 
 
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Last revised: December 06, 2010

FM