In some parts of the United States telephone service is
available through the cable television company. This version of telephone service is expected to grow rapidly
over the next five years. The
telephone traffic is carried on the same cable as the television programming.
In some installations there is an adapter between the cable line and the
house telephone wiring that replaces the network interface installed by the
local telephone company. This adapter essentially “peels off” the telephone
traffic data from the television signals and interfaces to the existing
telephone wiring so that the existing telephone equipment works the same as it
did before the installation. In
other installations the cable set-top box includes a telephone line connector,
an RJ-11 jack. Users can plug any
analog telephone device into this jack to place or receive calls.
There is no operational connection between the telephone service and the
cable television service, such as an on-screen display of telephone features,
etc. Users are required to provide
their own CPE.
Note: the performance of cable telephony regarding which Guidelines are addressed by the generic design should be the same as for a residential wireline telephone, assuming that a standard analog residential wireline telephone is connected to the cable box. Two cable telephony manufacturers assured us that their equipment was tested to these specifications. One manufacturer specifically tested the adapter for TTY signal compatibility. Note however that cable telephony switching systems may impose other barriers, or offer other solutions than conventional wireline telephony CO switches.