Nortel Norstar expert

Looking to hire a remote engineer for remote work in USA. Tech must be proficient with Nortel Norstar DR5.1 , and other network devices. Tech must represent themselves with best customer service and tech support standards. We have a customer who is having issues with their nortel Dr5.1. When they perform an inbound / outbound call on any phone, then put call onhold, then select a different line the phone would reset/reboot. we tried to reboot the system, swapped lines to isolate issue but issue unresolved. we attached photos and a video to help. We believe the system has failed but it is possible that we can factory default to resolve. Either way we are not experts and we need an skill pro to help with remote support. 1. work with carrier service providers 2. troubleshoot framing and timing 3. review logs 4. apply updates and patches 5. modify scripts 6. on call USA EST. Project Type: One-time project You will be asked to answer the following questions when submitting a proposal: What past legacy pbx systems have you had that is most like this one and why? Have you worked troubleshoot, reprogrammed with Nortel systems?