Talk:Digital telephony
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This is an important subject of both current and historical importance, that can become a major article. Here's a skeleton for a more detailed article:
- early experiments with PCM telephony
- the 8-bit, 8kHz standard
- DS0 as the basic digital telephony bitstream standard
- non-linear quantization: A-law vs. μ-law, and transcoding between the two
- bit error rate and intelligibility
- first practical systems put into service
- the U.S. T-carrier system, and the European E1-based system developed to carry digital telephony
- introduction of space-time switching in fully digital telephone exchanges
- replacement of tone signaling with digital signaling for trunks
- termination of DTMF traffic at exchanges
- in-band signaling vs. out-of-band signaling
- the problem of bit-robbing
- development of SS7
- emergence of fiber optic networking allows greater reliability and call capacity
- transition from plesichronous transmission to synchronous systems like SONET/SDH
- optical ring networks further increase reliability
- digital/optical systems revolutionize international long-distance networks, particularly undersea cables
- digital telephone exchanges eliminate moving parts, make exchange equipment much smaller and more reliable
- separation of exchange and concentrator functions
- roll-out of digital systems throughout the PSTN
- provision of intelligent network services
- digital speech coding and compression
- speech compression on international digital trunks
- phone tapping in the digital environment
- introduction of digital mobile telephony, specialized compression algorithms for high BER
- voice over ISDN: direct digital termination to customers
- the effects of digital telephony, and digital termination at the ISP, on modem performance
- voice over IP as a carrier strategy
- emergence of ADSL leads to voice over IP as a consumer product
- convergence of VoIP, mobile telephony, etc.
- flattening of telephone tariffs, increasing moves towards flat-rate pricing as the marginal cost of telephony drops further and further
-- Karada 23:03, 29 October 2005 (UTC)
