It’s hard to argue with the NTP. I have one other suggestion from the NTP’s and it is End-to-End Signaling
A call must be established before using the EES feature. An outgoing call is considered established 14 seconds (DP trunk) or four seconds (2500-type telephone or Digitone trunk) after the last digit has been outpulsed. The length of this delay can be changed through service change. EES can be performed after end of dial time out, or when answer supervision has been received from the far end, by pressing the octothorpe key (#) after the last digit.
LD 15
REQ: CHG Change.
TYPE: FTR
CUST
- EEST (NO) YES
NO = No EES feedback tone is given to the telephone. For Small Systems, DTMF should be set to NO.
YES = EES feedback tone is given; the type is defined by the DTMF prompt.
- DTMF (NO) YES
NO = Use EES for single feedback tone. For Small Systems, DTMF should be set to NO.
YES = Use EES for DTMF feedback tone.
To get uniform feedback tone when using the ADL key along with manual dialing, set the DTMF prompt to NO in LD 15.