The 21-180 is a synchronous 64kbps modem for codirectional clock environments that can be used to extend the reach of balanced G.703 interfaces up to 2km allowing for a cost effective transmission without electromagnetic interference and signal degradation.
The modem can use the incoming clock from the G.703 interface and propagate it down the fiber or use its internal clock source running at PDH accuracy. The modems automatic clock phase adjustment accommodates for any fiber round trip delay.
The 21-180, Fiber optic G.703 64kbps codir converter is intended to extend distance and to provide galvanic isolation for disturbance free insertion of 64kbps data into SDH/PDH – multipliers.
The converter is compatible with the FOT module in ABB’s tele protection terminals 550/560 for connecting the terminals to higher order networks.
Fiber optic G.703 64kbps
Codirectional
The ITU-standard “G.703 64kbit/s codirectional interface” describes a galvanic interface.
This interface is commonly used by tele protection equipment for connection to telecom multiplexers.
The 21-170 converts the codirectional interface signals to a proprietary fiber optic protocol used for example by tele protection equipment from ABB.
G.703/704 E1
Unbalanced
The ITU-standard G.703 describes the physical and electrical characteristics of hierarchical digital interfaces at rates up to 140 Mbps.
G.704 describes frame structures on G.703 interfaces up to 45 Mbps.
E1 describes a galvanic G.703 interface with G.704 frames at 2048 kbps commonly used in telecommunication.
