Any smart Fire/Smoke detectors compatible with Alarm wiring?

TurboSam said:
I've looked at the Elk two way wireless but would need to upgrade my wireless receiver which would them make obsolete some (most?)of my other wireless inputs.
You can have two types of wireless receivers connected to the M1.  If you go that route, it won't obsolete all your existing wireless gear.
Elk doesn't recommend it because it makes configuration a bit more complex.  The Elk two-way wireless receiver needs to be configured at address 2.  So if you already have something else at that address, it will require changing zone assignments around. 
@TurboSam - lol - ironically, when I sold the last house, that was one of the concessions I made - to pay their electrician to replace all the detectors!  They were over 10 years - for the price, it wasn't worth fighting.  That said, that house had fire sprinklers which made me feel a lot better!
I have not come to a conclusion yet.  I think I'd like combo CO2/Smoke units, but there are limited options that have that and interconnection and any smarts...  So far, my research has been deflating at best - and I haven't had time to pick it back up.  Luckily that one early morning disruption was the only one... that night, the guest bedroom one started chirping about the battery so I assume it's related.  I changed the battery, and haven't had beeping since.
TurboSam said:
I've had a string of chirping, beeping, or screeching from smokes that are close to (if not over) the ten year mark, and so I am looking for a complete house refresh in something battery operated and standalone.
We just bought an existing 28 year old house in the Idaho Panhandle. While painting the living room, I took down the purple (yes, purple) smoke alarm  in the LR and found it said "Expires 2008." If it had the typical ten-year life, it suggests it was installed about 1998 not long after the house was built. The sellers have not done anything to these alarms for TWENTY years! Egads.
I installed a quick BRK replacement smoke alarm from Home Depot or Lowe's at that one location. The nice thing is that it plugged right into the AC pigtail and it immediately sounded the others in the house when I pressed "Test." Even though a lot of this stuff is ages old, it's nice to have modern devices plug right in and work.
Now I have to replace all the other smoke alarms and the smoke detectors and heat rise detectors throughout. The smoke detector on the second floor is (strangely) not situated at the top of the stairwell -- it's on a sidewall in a hall landing somewhat below the highest point in the stairwell.
RAL:  thanks for the reminder about the two-way system.  I currently have two Elk wireless receivers (one the old M1XRF2G and the other the newer M1XRFEG).  I put the newer one in for broader coverage because the original one is on a second floor and some of the wireless sensors are in the basement.  I could certainly take out the old M1XRF2G and replace it with a two-way, but given the expense of it and the two-way smokes, I'm more inclined to go with the stand-alone dual sensor models.  I would dearly love hardwired security sensors and smokes (like Steve's), but in a house this old, it would be a huge (and expensive) task.
Steve:  I wonder if you second floor smoke is on the sidewall because they couldn't (or didn't) get the wiring to the top of the stairwell (assuming it is hardwired like the others)