Family telephone system

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The family telephone system ( FTA , initially marketed as a family telephone , internally referred to as a home telephone system) was a telecommunications solution that was offered to private households by the Deutsche Bundespost in the 1980s . Technically speaking, it was a series of small telephone systems for up to five extensions and a maximum of two trunk lines .

background

Data services such as the Internet were not significant at that time. The family telephone system should, on the one hand, enable internal calls and, on the other hand, make the double connection (two exchange lines) usable for larger groups of people. The solutions offered at that time with "In addition to apparatus" were compared to existing systems (such as ISDN PBXs or DSL - routers ) relatively inflexible. The target group were therefore larger households (based on the number of people or the size of the apartment) as well as small businesses with up to five branches.

Structure and types

The family telephone system consisted of a central electronic unit, roughly the size of a thick book, which required access to the telephone connection and a 220 V mains connection. There was always a "main office" (also known as "answering station") and up to four additional "extensions". All telephones were each connected analog via two wires . Thus, in contrast to the telephone systems customary up to that time, ordinary telephones without an earth button could be used as main and extension telephones . The family telephone systems were delivered in "standard equipment", extended performance features of the "supplementary equipment", which were offered by other (more expensive) telephone systems, were not provided. In addition, the possible connection length of the extension cables was limited to a cable length of approx. 170 m with a wire diameter of 0.6 mm.

designation Type Dimensions
W x H x D in cm		 Manufacturer Trunks Headquarters Extensions additional
HTA 1/4 121 (A) 16.4 x 22.6 x 8.1 Development group north:
BOSSE TELEFONBAU , elmeg , Hagenuk 		1 1 4th Connection option for door speakerphone and external alarm clock
HTA 1/4 122 20.5 x 21.8 x 6.4 Development group south:
Siemens , Merk , TeKaDe 		like type 121
HTA 1/4 123 18 × 24 × 10 SEL like type 121
HTA 1/4 124 like type 121
HTA 1/4 125 18 × 25 × 12 SEL like type 121
HTA 1/4 126 16.4 x 22.6 x 8.1 Development group north:
BOSSE TELEFONBAU, elmeg, Hagenuk		 like type 121
FTA 2/4 131 1 or 2 1 4th Connection option for door intercom and external alarm clock
FTA 2/4 133 18 × 24 × 12 like type 131
FTA 2/4 137 20 × 21 × 8.5 like type 131
  • Home telephone system type 121

  • Front view

  • Side view with nameplate

  • Rear with connection strip

  • System board

  • Family telephone system type 137

  • Front view

  • Side view with nameplate

  • System board

Performance characteristics

  • Connection option for up to five extensions
  • 1 or 2 trunk lines (marketed by the Bundespost as a double connection)
  • Internal conversations
  • Brokering between internal and external calls
  • Acceptance of external calls at any extension
  • Transferring calls to other extensions
  • Connection of a door intercom system including door opening from every extension
  • Use of a single extension even in the event of a power failure

costs

List of costs for setting up and renting a family telephone system as of June 1981:

  • The connection of a Swiss Post's own (rented) family telephone system cost 80 DM once .
  • The connection of the microphone units cost 40 DM once per microphone unit.
  • The current fee for the FTA including two intercoms was 25 DM per month or 1070 DM once, then the monthly fee was 4 DM.
  • The monthly fee for the third to fifth intercom was DM 1.90 each.
  • The door hands-free system cost 10 DM per month or 560 DM once.

Economic failure

Despite the extensive features for the time , the family telephone system could not establish itself and was taken out of the range after 1990. The main reason for this may have been the price: the hardware of a fully developed family telephone system had a market price between 1000 and 1500 DM (depending on the end devices used). However, due to the terminal monopoly of the Bundespost, these had to be rented in full from the Bundespost; Depending on the end device, a monthly rent of DM 100 was quickly achieved (the cheapest telephone with a rotary dial cost DM 2.30 per month, the cordless telephone from the Sinus series cost DM 120). In addition there were the costs for the central unit, the actual connection and call charges.

literature

  • Instruction sheets of the Deutsche Bundespost - Telecommunications - Edition B
    • Year 36/1983 No. 3: Heinz-Wilhelm Arend, FAm (B 1107.03.83 Mü) FA Kassel: The registration service for telecommunications equipment at the DBP ; Page 79-99
    • Volume 37/1984, No. 10: Gottfried Zilz, PR (B 1203.10.84 G) BPM Bonn: Reorganization of the speaking equipment according to the 25th Amendment to VFO ; (1.3.6 Advance charge for intercoms for family telephone systems and private branch exchanges); P. 334; Page 331–339
    • Volume 38/1985, No. 6: Page: 252, 256 and 257
    • Volume 40/1987
      • No. 3: MultiTel - the multifunctional telephone of the DBP - telephony and screen text at the same time ; Press release, February 3, 1987; Page 113
      • No. 9: MultiTel, the multifunctional telephone, now with a color screen ; Press release, June 30, 1987, page 354
    • Year 41/1988, No. 2: Telecommunications regulations come into force on January 1st ; Press release, December 28, 1987, p. 97
  • Dietrich Reinmund: New family telephone for two exchange lines in: Fernmelde-praxis , No. 10, May 25, 1984, pp. 395–404
  • Hermann Bauer: The home telephone system in: rfe - The young radio, television and industrial electronics engineer, part 1: 9/1983, p. 421, part 2: 10/1983, p. 475, part 3: 11/1983, p 523

Individual evidence

  1. ↑ a b c d e The home telephone system : instruction sheets of the German Federal Post Office, issue B Telecommunications, 2/1982, p. 55
  2. ↑ Mention of the family telephone system
  3. ↑ a b Deutsche Bundespost TELEKOM: Handbook for suppressors , 03/1993
  4. ↑ Post family telephone - home telephone system HTA - Type 126 : Working group home telephone system HTA: BOSSE TELEFONBAU & elmeg & Hagenuk, August 1982
  5. ↑ a b c Family telephone system 2/4 : Service manual of the Deutsche Bundespost for type 133, 2/1984
  6. ↑ 10,000 family telephones in the network of the German Federal Post Office : Instruction Sheet of the German Federal Post Office, Issue B Telecommunications, 8/1981, p. 295