A
Organization of the work of ITU-T
B
Means of expression: definitions, symbols, classification
C
General telecommunication statistics
D
General tariff principles
E
Overall network operation, telephone service, service operation and human factors
F
Non-telephone telecommunication services
G
Transmission systems and media, digital systems and networks
H
Audiovisual and multimedia systems
I
Integrated services digital network
J
Cable networks and transmission of television, sound programme and other multimedia signals
K
Protection against interference
L
Construction, installation and protection of cables and other elements of outside plant
M
Telecommunication management, including TMN and network maintenance
N
Maintenance: international sound programme and television transmission circuits
O
Specifications of measuring equipment
P
Terminals and subjective and objective assessment methods
Q
Switching and signalling
S
Telegraph services terminal equipment
T
Terminals for telematic services
V
Data communication over the telephone network
X
Data networks, open system communications and security
Y
Global information infrastructure, Internet protocol aspects and next-generation networks
Z
Languages and general software aspects for telecommunication systems