what frequency is used in my 78258 area as I need booster or repeater antenna

My ADT system uses Telit H24 DB/2100 wireless module.  This covers 850, 1900,/1700-2100 and comes with a small antenna.  The module itself has 2 additional sockets for a total o 3 antennas.  My neighborhood has 1 or 0 bars for AT&T, Verizon & Sprint and we use WIFI-C to make calls as our phones support wifi calling.

ADT does not support WIFI-C calling and I am no longer able to make an outgoing alarm call.  I discontinued my AT&T analog line as it was $51 a month and 4-8 calls a day were spoof'ed caller ID spam even though number had been on do-not-call list for several years.  Antennas, even repeaters are inexpensive compared to $51 a month but I need to know what frequency was being used by AT&T in my neighborhood as the boosters are different for each band.  I have the adapter to connect the Telit module to RG59 cable that the ADT tech left me with along with a length of cable to reach the roof.

ADT does not have a community forum so and I suspect others have the same problem.  A booster does not work if no signal and usually I have 1 bar, sometimes 2 and a few times 0 bars.  It would be nice to hear from someone who has done this but ADT is not in for forum / community support unlike AT&T

[EDIT] Problem solved:  ADT replaced their AT&T module with a Verizon one.  I did find out from tech support my area has LTE and the frequency is negotiated with the phone so I would have had to get a multiple antennas to cover any band the phone switched to (supposedly according to tech support on chat line).