Maxim Integrated Teridian V.22 bis Linux Softmodem for 73M1822/73M1922 MicroDAA - Manual (Page 56)

V.22 bis Linux Softmodem for 73M1x22 MicroDAA User Guide UG_1x22_043
56 Rev. 1.5
Continuous cadence:
The tone is continuously present and provided that it meets the requirements for frequency
and level, it will be considered as a valid call progress tone after a certain time of validation
(see S67 or S23). This is the standard cadence for dial tone detection in most cases.
Continuous
Validation time
Single cadence A:
The cadence has a regular On and Off time, A, and provided that it meets the requirements
for frequency and level, it will be considered as a valid call progress tone after a certain
time of validation (see S67 or S23).
Single Cadence A
Cadence A min and max On time
Cadence A min and max Off time
+ Validation time
Single cadence B:
The cadence has a regular On and Off time, B, and provided that it meets the requirements
for frequency and level, it will be considered as a valid call progress tone after a certain
time of validation (see S67 or S23).
Single Cadence A
Cadence A min and max On time
Cadence A min and max Off time
+ Validation time