GE Hydran 201i Instruction Manual page 150

If desired, the user can install their own modem, although a few settings must be
expected to make it functional.
When using a modem, each Hydran 201Ti can be set to either one of the two
following modes (in the Communication submenu; see Section 5.5.6):
• Call OnAlarm: In this mode, the H201Ti communicates with the Hydran Host
software through a telephone line each time a gas or fail alarm condition is
detected (to select this mode, see Section 10.6.3).
• AnswerOnly: In this mode, the H201Ti remains silent until a host computer
running the Hydran Host software communicates with it.
Page 150
Figure 10-5: Typical Communication Configuration with a Modem
Hydran* 201i Instruction Manual
MA-033 Rev. 14.0, 12-Nov-18