Null modem connection via serial interface

Setting the IP address of the ChemWeb Server

Null modem connection via serial interface

Via the integrated RS232 interface “COM1 Null modem” of the ChemWeb Server, a serial connection can be set up to a laptop computer or PC, using a modem cable. It is possible to parameterize and operate the ChemWeb Server via this connection.

For this purpose, a modem cable (9/9-contact, jack-plug, 1:1) is required.

Switchover of ChemWeb Server to null modem operation

To access the ChemWeb Server via the RS232 interface, a possibly existing internal modem (analog or ISDN) must be disconnected. For this purpose, short-circuit the digital input IN2 by means of a wire jumper. Then the ChemWeb Server must be restarted by switching off the power supply and pressing the Reset button.

For ChemWeb Servers without modem (AAC5557), this wire jumper is already installed in the factory, i.e.: this version always works in the null modem mode.

As soon as the ChemWeb Server has been adapted to null modem operation the internal modem is no longer available! Only after removing the wire jumper from digital input IN2 and after a restart can the internal modem be used again.

Installing a null modem driver

WindowsXP includes a driver for the direct connection between two PCs, which must, however, be reinstalled manually. To install the driver, select the menu item “Phone and Modem Options” from the left window under “Control Panel” ==> “Network and Internet Connections”

Select the menu item “Phone and Modem Options” from the left window.

Select the “Modems” file card and click “Add”.