In  the  Call  OnAlarm  mode,  the  following  actions  are  performed  when  an  alarm  is 
triggered: 
•  The  H201Ti  sends  the  ATDS0  command  through  the  selected  communication 
channel  (USB  or  supervisory  link;  see  the  CommChannel  and  DefaultChannel 
parameters in the Communication submenu). 
•  The  Hayes-compatible  modem  receiving  this  command  dials  the  telephone 
number  previously  stored  in  its  register  0;  this  number  is  redialed  until  the 
connection  with  the  host  computer’s  modem  is  established.    Then,  no  other 
message is sent; the host computer has the responsibility to communicate with 
the H201Ti in alarm. 
•  The Hydran Host software answers and receives the alarm message. 
•  The Hydran Host software displays the alarm states and updates its data bank. 
•  The user must acknowledge the alarm in the Hydran Host software and take the 
appropriate measures.  
Note:   
1. This functionality is only supported in Hydran protocol and Hydran Host PC application. 
It is not supported by Perception software (when Hydran 201Ti is set to Modbus protocol) 
2.  It  might  take  up  to  15  min  after  the  alarm  is  generated  in  the  H201Ti  for  the  Call 
OnAlarm to the Host software to occur. 
2. Acknowledging the alarm in the Hydran Host software does not turn off the illuminated 
push-button of the Hydran 201Ci-1 Controller. 
 
10.4  Communication Protocol 
Hydran 201Ti only supports serial communications and for this type of connectivity, 
General Electric Canada uses its own protocol – Hydran protocol, and starting with the 
CPU FW v4.0, it also supports standard Modbus RTU protocol (see Appendix I). In the case 
of  the  Hydran  protocol  data  is  transmitted  in  ASCII  codes;  data  clusters  being 
transmitted are verified and, if necessary, transmitted again.