Electronic and Postal Communications (Quality of Service)
G.N. No. 416 (contd)
neither the call is
answered nor the called
party busy tone nor
ringing tone is
recognized at the access
of the calling user within
40 seconds from the
instant when the last
digit of the destination
subscriber number is
received by the network.
5
R-Value
Transmission Rating
Factor R is the primary
output of the E-model
defined in ITU-T Rec.
G.107/ G.108
For best quality: 90≤ R < 100
For high quality: 80 ≤ R < 90
For medium quality:70 ≤ R <
80
[ITU-T Rec. G.109]
6
Values on a predefined
scale that subjects assign
to their opinion of the
performance of the
telephone transmission
system used either for
conversation or for
listening to spoken
material. Apart from
subjective opinion, the
abbreviation "MOS" is
also used for scores that
originate from objective
models or network
planning models.
Mean Opinion Score (MOS)
Objective assessment based
MOS should be greater than 4
on conversion of R-value.
(ITU-T Rec. G.107)
Subjective assessment based
on use of telephone user
surveys.
(ITU-T Rec. P.82)
18