Honeywell HC900 User And Installation Manual page 153

Modem configuration
Before connecting a modem to the controller's RS-232 port (marked "CONFIGURATION"), the modem
must be configured with the following settings:

Baud Rate = 1200, 2400, 4800, 9600, 19200, 38400, 57600 (Must match Baud Rate configured in
HC900 Controller)

Parity = None

1 stop bit

8 data bits

No handshaking

Ignore DTR

Suppress result codes

Suppress echo

Auto answer

Disable command recognition (only necessary if the modem has this capability)
Some of these settings may be settable via switches. Others may require command strings to be written to
the modem using a PC terminal program such as Hyperterminal. You will need to refer to your modem's
documentation to make this determination. Those settings that are configured using command strings must
be saved to the modem's non-volatile RAM (NVRAM), and the NVRAM must be configured as the profile
that gets loaded when the modem is powered up.
Most modems are equipped with auto-recognition to set the baud rate, parity, stop bits, and data bits. If
your modem has no means of setting these using switches, then most likely it is equipped with auto-
recognition. To configure the port settings of a modem with auto recognition, do the following:
Step
1
Connect the modem to a PC.
2
Power up the modem.
3
Start up a PC terminal program such as Hyperterminal.
4
Configure the PC COM Port for 1200, 2400, 4800, 9600*, 19200*, 38400*, 57600 baud (must
match Baud Rate configured in HC900 Controller), no parity, 1 stop bit, and 8 data bits.
*recommended
5
Establish communications with the modem. A common way of doing this is simply entering the
AT E1 Q0 command and seeing if the modem responds with OK.
Once you establish communication to the modem, its port settings are configured.
6
Save the port settings to the profile that gets loaded on power-up.
Revision 6
21 April 2017
HC900 Process & Safety Controller User and Installation Manual
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