1
Introduction
1.1 General
1.2 Definitions
2 Characteristics of interfaces
2.1 Two-wire analogue interfaces
2.1.1 Interface Z
2.1.2 Interface C2
2.2 Four-wire analogue interfaces
2.2.1 Interface C1
2.3 Digital interfaces
2.3.1 Interface A
2.3.2 Interface B
2.3.3 V-type interfaces
3 Voice-frequency parameters of a
connection between two interfaces of the same exchange
3.1 General
3.2 Transmission loss through the
exchange
3.3 Group delay
3.3.1 Absolute group delay
3.3.2 Group delay distortion
3.4 Noise and total distortion
3.4.1 Weighted noise
3.4.2 Total distortion including quantizing distortion
3.5 Crosstalk
3.6 Discrimination against out-of-band
signals applied to the input interface
3.7 Spurious out-of-band signals
received at the output interface
3.8 Echo and stability
4 Exchange transfer function –
jitter and wander
Annex A – Information
on the formulae used in this Recommendation to calculate weighted noise and
signal-to-total distortion ratio
A.1 General
A.2 Weighted noise
A.2.1 Weighted noise for an input connection originating from a Z-interface
A.2.2 Weighted noise for an output
connection terminating in a Z-interface
A.2.3 Weighted noise for a whole connection originating from and terminating
in a Z‑interface
A.2.4 Weighted noise for an input connection originating from a 2-wire or
4-wire C‑interface with or without signalling on the speech wires
A.2.5 Weighted noise for an output connection terminating at a 2-wire
C-interface with Lo ³ or a 4‑wire C-interface
both with or without signalling on the speech wires
A.2.6 Weighted noise for an output connection terminating at a 2-wire
C-interface with Lo < -5 dBr and with or without
signalling on the speech wires
A.2.7 Weighted noise for a whole connection originating from and terminating
in 2-wire or 4‑wire C‑interfaces with or without signalling on the
speech wires
A.3 Total distortion including
quantizing distortion
A.3.1 Total distortion including quantizing distortion for an input
connection originating from a Z-interface
A.3.2 Total distortion including quantizing distortion for an output
connection terminating in a Z‑interface
A.3.3 Total distortion including quantizing distortion for a whole connection
originating from and terminating in a Z-interface
A.3.4 Total distortion including quantizing distortion for an input
connection originating from a 2-wire or a 4‑wire C-interface
A.3.5 Total distortion including quantizing distortion for an output
connection terminating in a 2‑wire or a 4‑wire C-interface
A.3.6 Total distortion including quantizing distortion for a whole connection
originating from and terminating in 2-wire or 4-wire C-interfaces