EV6240 Datasheet, PDF (40/47 Pages) CML Microcircuits – Opto-Isolated serial interface capability

Evaluation Kit for CMX624/CMX644A
EV6240
State 5
Wait until 2225Hz Answer tone or High Band Unscrambled PSK 1’s (marks) frequency has been
detected.
If 60ms Timer has expired.
Goto State 6a.
Else
Silence period is too short so Hang Up and Exit.
If the Wait for Carrier after Dial Timer expires then Hang Up and Exit.
State 6
Wait until 2225Hz Answer tone is detected then goto State 6a.
If the Wait for Carrier after Dial Timer expires then Hang Up and Exit.
State 6a
Start a 160ms Timer.
If 160ms Timer expires goto State 7.
If 2225Hz Answer tone is not detected then goto State 6.
State 7
Disable 2225Hz Answer tone detection.
Check Communications Standard selected by user (Bell or ITU-T).
If Bell
Start a 550ms Timer.
Else
Start a 450ms Timer.
State 8
Wait until 450ms or 550ms Timer expires
Set up the CMX644A to Tx Low Band Scrambled PSK 1’s (marks).
Restart Validation Timer (setting stored in S18).
Set up CMX644A to detect High Band Scrambled PSK.
State 9
When the PSK Carrier Detect flag is set the Rx data is monitored to ensure 95% of 1’s are detected
for 270ms.
If 95% of High Band Scrambled PSK 1’s are detected for 270ms
Turn on Modem CD LED.
Start a 770ms Timer.
Goto State 10.
If Validation Timer expires before 95% of High Band Scrambled PSK 1’s detected then Hang Up and
Exit.
State 10
Wait until 770ms Timer expires then goto Data Transfer Mode.
40
© 1999 Consumer Microcircuits Limited
UM6240/3