I have one X16 system I put in for someone a few weeks ago. they have one annoying problem with making outside calls.

they have to dial slowly for calls to go through properly.

if they dial too fast they get a telephone company recording. it's almost as if the touch tones don't all go through.

this is happening on two telephones.

all wiring is looped, i have 4 phones on blue pair and 4 phones on green pair.

xblue says its the phone company, customer never had this issue with their casio 4 line phones. telco is verizon fios.