Reasonable question. Dexcom Support also asked. I wanted to be sure they understood this is not simply an academic question nor am I merely trying to find a hole in the system.
Everybody uses the system differently.
For a parent, the alarms on the pump are not helpful. Unless I switch back to the old baby monitor that I used to use with the Dex 7. The Smart Phone transmitting through the Dex App and onto the Dex Follow App to a bed-side Android Tablet is nice - that helps. But there are so many links and moving parts in the data transmission that I am not willing to trust this for overnights. I will gladly use it as a secondary alarm source but not the primary. The Dexcom Receiver can be placed in the parent’s bedroom against an adjoining wall to a child’s bedroom and reliably pick up the transmitter from the child and have loud alarms in the room with the parent at nighttime.
As well, when driving in the car, the receiver can easily be glanced at while driving to see the BG of the child. Obviously the parent can not look at the pump so that is out. Looking at a smart device while driving is a safety hazard. The benefit of the receiver is it can be picked up and the button pressed without looking at it. A 1/2 second glance at the Dex Receiver then shows both BG and graph for direction. If not good, we can pull to the side of the road, make any correction necessary and get back to driving.
Neither Dexcom nor Tandem stated in advance that Dexcom Receiver functionality would be compromised with the Tandem X2/G5 integration update. As far as I know, neither company has made public statements to that effect either. Absent such, I fully expect the technology to continue working. As the manufacturer of the Transmitter and the Receiver, I am placing the onus on Dexcom. I do expect them to arrive at a solution and make this work.
Dexcom Technical Support told me this works (Tandem t:slim X2 pump, Dexcom G5 Receiver and Smart Phone all simultaneously paired to a Dexcom G5 transmitter). They have also told me they are working on a solution that will rectify the problem I am having in not being able to get this to work. They have not let me down to date and I am optimistically expecting them to once again deliver a proper solution.