Error performance monitoring system for digital exchange circuit

An error performance monitoring system for each call in a digital exchange circuit having at least a plurality of subscriber terminals, an exchange system coupled with said subscriber terminals, and transmission system which includes a plurality of circuits forming transit paths, said system comprising:

• a transmission error check information storage coupled with said transmission system for collecting and storing error check information of each transit path together with collected time of said information,
• call information storage coupled with said exchange system for collecting and storing call information including a call identification with terminal numbers of an originating subscriber terminal and a terminating terminal, transmission rate, start time and end time of a call and circuits which said call is routed,
• a circuit accommodation database storing information indicating which of said circuits form each path, and
• end-to-end transmission error performance evaluation means for calculating error performance of each call between an originating terminal and a terminating terminal through a digital exchange system and a transit path according to said error check information, said call information, and said circuit accommodation database.