Cal. Civ. Code § 1941.4

The lessor of a building intended for the residential occupation of human beings shall be responsible for installing at least one usable telephone jack and for placing and maintaining the inside telephone wiring in good working order, shall ensure that the inside telephone wiring meets the applicable standards of the most recent California Electrical Code, and shall make any required repairs. The lessor shall not restrict or interfere with access by the telephone utility to its
telephone network facilities up to the demarcation point separating the inside wiring.
“Inside telephone wiring” for purposes of this section, means that portion of the telephone wire that connects the telephone equipment at the customer’s premises to the telephone network at a demarcation point determined by the telephone corporation in accordance with orders of the Public Utilities Commission.