G series - technical definition

The ITU-T Recommendations addressing transmission systems and media, digital systems and networks. See Table G-1 for selected G-series Recommendations. For a full listing of ITU-T Recommendations, see the contact information in Appendix A.

Table G-1: G-Series Recommendations

Recommendation	Description
G.168	Digital network echo cancellers
G.169	Automatic level control devices
G.651	Characteristics of a 50/125 µm multimode graded index optical fibre cable
G.652	Characteristics of a single-mode optical fibre and cable
G.653	Characteristics of a dispersion-shifted single-mode optical fibre and cable
G.654	Characteristics of a cut-off shifted single-mode optical fibre and cable
G.655	Characteristics of a non-zero dispersion-shifted single-mode optical fibre and cable
G.665	Generic characteristics of Raman amplifiers and Raman amplified subsystems
G.694.1	Spectral grids for WDM applications: DWDM frequency grid
G.694.2	Spectral grids for WDM applications: CWDM wavelength grid
G.702	Digital hierarchy bit rates
G.703	Physical/electrical characteristics of hierarchical digital interfaces
G.704	Synchronous frame structures used at 1544, 6312, 2048, 8448 and 44,736 kbit/s hierarchical levels
G.705	Characteristics of PDH equipment functional blocks
G.711	Pulse code modulation (PCM) of voice frequencies
G.722	7 kHz audio-coding within 64 kbit/s
G.722.1	Low-complexity coding at 24 and 32 kbit/s for hands-free operation in systems with low frame loss
G.722.2	Wideband coding of speech at around 16 kbit/s using Adaptive Multi-Rate Wideband (AMR-WB)
G.723.1	Dual rate speech coder for multimedia communications transmitting at 5.3 and 6.3 kbit/s
G.726	40, 32, 24, 16 kbit/s ADPCM
G.727	5-, 4-, 3-, and 2-bit/sample embedded ADPCM
G.728	Coding of speech at 16 kbit/s using LD-CELP
G.729	Coding of speech at 8 kbit/s using CS-CELP
G.729.1	G.729 based Embedded Variable bit-rate coder: An 8-32 kbit/s scalable wideband coder bitstream interoperable with G.729
G.983.1	Broadband optical access systems based on Passive Optical Networks (PON)
G.991.1	High bit rate Digital Subscriber Line (HDSL) transceivers
G.991.2	Single-pair high-speed digital subscriber line (SHDSL) transceivers
G.992.1	Asymmetric digital subscriber line (ADSL) transceivers
G.992.2	Splitterless asymmetric digital subscriber line (ADSL) transceivers
G.992.3	Asymmetric digital subscriber line transceivers 2 (ADSL2)
G.992.4	Splitterless asymmetric digital subscriber line transceivers 2 (splitterless ADSL2)
G.992.5	Asymmetric Digital Subscriber Line (ADSL) transceivers - Extended bandwidth ADSL2 (ADSL2+)
G.993.1	Very high speed digital subscriber line transceivers
G.993.2	Very high speed digital subscriber line transceivers 2 (VDSL2)