Tadiran Telecom Emerald ICE Installation & Maintenance Manual page 32

functions/operations and two channels are used for the digital voice channel
requirements.
Each digital station interface is protected against circuit wiring shorts by an
over‐current protection Polyswitch. The digital station circuit requires only one
cable pair to operate and is not polarity sensitive.
Physical connection of digital extensions, power failure telephones and CO lines to
the 610+2 board is made through a 25 pair amphenol connector to be terminated
on the MDF. (Main Distribution Frame)
2-7
Emerald ICE Installation & Hardware Reference Manual