R2621 fails to interconnect with the switch of Ericson by R2 signaling of E1VI module.
Change the signaling used by Ericson switch to No. 1 Chinese signaling, and the interconnection is succeeded, and session is normal then.
By default, the E1VI module of R2621 is configured with No. 1 Chinese signaling when configuring R2 signaling;that what is used by the switch from Ericson at the peer is also R2 signaling. However, R2 is a basic one that could generate multiple variations. Thus, the variation derived from R2 signaling used by Ericson switch disagrees with that sued by R2621, failing the interaction.