Heath Consultants Heath Volume Corrector (HVC) - Manual (Page 10)

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Form “C” PCB (Optional)
This is an optional feature that adds two Form “A” pulses for Corrected and two for Uncorrected.
External Modem
The HVC 325 is equipped with two RS232 communication ports. “Com Port 1” is dedicated to local
direct communication at 19200 baud using the HVC “comm cable”. “Com Port 2” is used for connecting
a modem. Remote baud rates available are 300, 1200, 2400, 9600 and 19200. When configuring for a
remote modem, the “Remote Modem Baud Rate” in the unit MUST match the baud rate of the field
modem being used.
NOTE: The “Remote Port” must have RX, TX, and GND connected (RTS is required for the
“call out upon alarm” feature).
NOTE: When connecting the HVC to an external modem, it is recommended to connect external power
to the HVC due to higher current demand. If not, the primary alkaline battery pack’s run-time will be
reduced.
Internal Modem
The HVC 325 may be equipped with an internal modem and phone line surge suppressor. The internal
modem is a 2400-baud modem. The modem is pre-configured and pre-wired from the factory, ready for
remote communication. If the HVC is equipped with the phone line suppressor, it will be connected
directly into the modem’s RJ-11 connector. A 12-volt battery pack (8 “AA” batteries) is supplied, but not
connected when shipped. The user must connect prior to remote communication. Assuming one two-
minute call per day, every day, the battery should provide approximately 2 years of service.
The optional phone line surge suppressor will sacrifice itself to protect the equipment in the event of a
destructive power surge on the phone line.
To connect a phone line to the modem, insert the phone cable through the black wire gland on back of the
case (see Figure 1). The cable must be terminated with a RJ-11 connector. Plug into surge protector if
provided; otherwise, plug directly to the modem.
CAUTION: The HVC must be connected to earth ground to allow the surge suppressor to operate
properly.
CAUTION: Internal modem option is not currently certified for use in hazardous environments. An
external modem should be used when necessary. Refer to drawing MTM-308-1 for field wiring
requirements on external power and modem connections to maintain intrinsic safety.
Alarms
All alarms can be reset manually by holding the scroll button closed for more than 4 seconds. They can
also be configured and reset by using the HVC Host. An active alarm will be indicated by a lower row of
dots on the LCD display.