| 摘要 |
A central office line card with distributed signaling voltages comprised of a plurality of subscriber line interface circuits connected to a common signal bus. Standard ringing signal is received from a remote generator within the central office and applied to the common signal bus via a first relay. A receptacle is provided on the line card for receiving a removable module containing circuitry for generating further signaling voltages such as party line ringing and coin telephone test and control voltages. Signals from the module are applied to the common signal bus via a further plurality of relays. Each of these subscriber line interface circuits is connected to the common signal bus via additional respective relays.
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