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VP9650+SMC2.0 Fails To Call the TE50, with an Error Message Indicating That There Is No Response To the TCP Connection or the TE50 Does Not Answer the Call

Publication Date:  2019-04-25 Views:  20 Downloads:  0
Issue Description

VP9650+SMC2.0 fails to call the TE50, with an error message indicating that there is no response to the TCP connection or the TE50 does not answer the call.

Handling Process

1. The IP address of the TE50 can be successfully pinged from the MCU. This indicates that the network is normal.

2. There is no firewall on the TE50 side, and therefore no restriction on the 1720 port.

3. The Wi-Fi hotspot of the TE50 is disabled, and the Wi-Fi network preferred function is also disabled. This rules out the possible reason that the default address of the wireless network is used for registration.

4. According to analysis on the packets captured on site, the SC returns an ACF message to the MCU, but after this the MCU does not send a setup connection request. It is found that the IP address of the TE50 is, which is in the same network segment as the default FE port IP address of the MCU.

It is suspected that the FE port is used to call the TE50 during call setup. After the FE port IP address of the MCU is changed to one that is not in the same network segment as that of the TE50, the call can be successfully made. 

Root Cause

The TE50 IP address and the default FE port IP address of the MCU are in the same network segment.


Change the default FE port IP address of the MCU.