Hello, odd combo prob. home telephone setup,one line in house dont know why they need this but, old nortel maestro phones, four of them , added 1 new aastra m9116 to the mix. What happens is that the aastra phone only rings once and all the others ring as many as you are dialing in. Aastra by it self with no maestros will ring normal. Are these not compatible?? both analog???