DS0

The data transmitted using Digital Signal level 0 must come from a digital device. The data rate of a DS0 is 64 kbps.  However, since AMI line coding requires 8 kbps of overhead, the very common 56 kbps circuit is also called a DS0.  This is confusing, but realize that even though it is called 56 k circuit, it is still sending 64 kbps through, and only 56 k of it is payload.  See the "Telecom 101" section for more info.

Load Coils  -  the DS0 can carry voice or data.  If the circuit is 64 kbps ISDN (BRI) or DSL, then the load coils must be removed (this is called "line conditioning").  A load coil is an Inductor (coiled wire) device for twisted-pair wire and is typically placed at 6,000-foot intervals. Voice transmission usually occurs in the 0-4kHz range, which the load coils are designed to enhance by blocking noise (high frequencies). Unfortunately, ISDN and DSL traffic is passed at much higher frequencies which load coils block - and therefore they must be removed for these services.  Removing load coils, the exact location of which are often unknown - can be very difficult for the LEC, and has been a major stumbling block in readying some neighborhoods for DSL.