Physical/Electrical Characteristics of Hierarchical Digital Interfaces - Series G: Transmission Systems and Media, Digital Systems and Networks Digital Terminal Equipments - General Study Group 15; Erratum 1: Covering Note: 07/20/2005
This Recommendation provides the recommended physical and electrical characteristics of the
interfaces at hierarchical bit rates as described in ITU-T Recs. G.702 (PDH) and G.707 (SDH), to
enable the interconnection of digital network components (digital sections, multiplex equipment,
exchanges) to form an international digital link or connection. The characteristics given in this
Recommendation should be applied to new equipment (component) designs.
NOTE 1 – The characteristics of interfaces at non-hierarchical bit rates, except n × 64 kbit/s interfaces
conveyed by 1544 kbit/s or 2048 kbit/s interfaces and 3152 kbit/s interface in North American hierarchy, are
specified in the respective equipment Recommendations.
NOTE 2 – The jitter specifications contained in this Recommendation are intended to be imposed at
international interconnection points.
NOTE 3 – The interfaces described in clauses 5 to 12 correspond to the ports T (output port) and T′
(input port) as recommended for interconnection in ITU-R Rec. F.596-1 (Interconnection of digital radiorelay systems).
NOTE 4 – For signals with bit rates of n × 64 kbit/s (n = 2 to 31) which are routed through multiplexing equipment specified for the 2048 kbit/s hierarchy, the interface shall have the same physical/electrical
characteristics as those for the 2048 kbit/s interface specified in clause 9. For signals with bit rates of
n × 64 kbit/s (n = 2 to 23) which are routed through multiplexing equipment specified for the 1544 kbit/s
hierarchy, the interface shall have the same physical/electrical characteristics as those for the 1544 kbit/s
interface specified in clause 5.
NOTE 5 – The specifications contained in this Recommendation are related to the physical interface only (i.e. to characterize the line codes and input/output equipment interfaces); in particular, the required
frequency tolerances do not imply overall equipment performances which may be driven by tighter
requirements in Recommendations for specific network/equipment applications (e.g. ITU-T Recs. G.813 and
G.783).
2 References