To setup SNMP for Sonus, please use the follwing reference:
https://support.sonus.net/display/UXDOC50/Sonus+SBC+1000-2000+Download+Center
Note also that community string should be low case, check firewall settings for UDP 162 and 161.
Use MIB browser to crack OID code for specific interface you want to monitor.
As example: