| 摘要 |
A method for connecting subscribers to form a conference call in a time division multiplex (TDM) telecommunication switching system having a TDM ring-like circuit running from subscriber to subscriber is described. A subscriber speech word is added to a pulse code modulated (PCM) word transferred to the subscriber station, and the summation PCM word is both retransferred and stored in the subscriber station for a time-slot frame. The stored preceding PCM word is subtracted from the PCM word transferred to the subscriber station, and the differential PCM word forms an aural signal. |
