| 摘要 |
PURPOSE: A method for assigning channels is provided to examine a local trunk interface(LTRI) performing link accesses between a remote switching module(RSM) and a host exchange station to assign the channels, only when the LTRI is in an activated status so that the RSM can receive digits from subscribers in an independently-operated status. CONSTITUTION: If an optional subscriber is hooked off to perform a call, a remote switching module(RSM) processor senses an off-hook state. The processor identifies whether a dual tone multi frequency(DTMF) signal corresponding to a called telephone number is capable of being received. The processor examines a link status with a host exchange station. The processor examines whether the link status is normal. If so, the processor performs a normal call processing routine and returns. If the link status is not normal because of a cable rupture or a link communication error, the processor converts a status of an RSM into an independently-operated status. The processor retrieves an internal memory to read an alarm register. The processor reads a local trunk interface(LTRI) number presenting an activated LTRI. The processor examines whether a DTMF signal is received from the subscriber. If so, the processor assigns a channel designated in the LTRI on the basis of the LTRI number, and switches the channel, then returns.
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