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Rebooted the system sometimes worked, but after some hours the problem reoccurred. &nbsp;Debugging info led us to believe that the internal memory was at fault, so we replaced it. &nbsp;It's been up for several hours now with no problems. &nbsp;Will post back the results.
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Rebooted the system sometimes worked, but after some hours the problem reoccurred.  Debugging info led us to believe that the internal memory was at fault, so we replaced it.  It's been up for several hours now with no problems.  Will post back the results.

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We have a Cisco UC520 that has been in use for many years with no configuration changes apart from user / extension amendments. &nbsp;We have 8 lines on an ISDN-30 connection with two incoming numbers: one for voice calls, the other for fax.<br />
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Currently the fax calls are working fine, and we can make outgoing calls. &nbsp;However, incoming calls on the main number connect but are immediately dropped. &nbsp;We have confirmed with the telco that there is no fault, and also rebooted the UC520 and the PoE switch that connects the phones.<br />
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How can we troubleshoot this problem? &nbsp;Thanks in advance.
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We have a Cisco UC520 that has been in use for many years with no configuration changes apart from user / extension amendments.  We have 8 lines on an ISDN-30 connection with two incoming numbers: one for voice calls, the other for fax.

Currently the fax calls are working fine, and we can make outgoing calls.  However, incoming calls on the main number connect but are immediately dropped.  We have confirmed with the telco that there is no fault, and also rebooted the UC520 and the PoE switch that connects the phones.

How can we troubleshoot this problem?  Thanks in advance.

Cisco UC520 drops incoming calls

Cisco PIX is a dedicated hardware firewall appliance; the Cisco Adaptive Security Appliance (ASA) is a firewall and anti-malware security appliance that provides unified threat management and protection the PIX does not. Other Cisco devices and systems include routers, switches, storage networking, wireless and the software and hardware for PIX Firewall Manager (PFM), PIX Device Manager (PDM) and Adaptive Security Device Manager (ASDM).

Cisco

IP telephony (Internet Protocol telephony) is a general term for the technologies that use the Internet Protocol's packet-switched connections to exchange voice, fax, and other forms of information that have traditionally been carried over the dedicated circuit-switched connections of the public switched telephone network (PSTN). Using the Internet, calls travel as packets of data on shared lines, avoiding the tolls of the PSTN. The challenge in IP telephony is to deliver the voice, fax, or video packets in a dependable flow to the user.