Appendix A. Changing COM220 Settings

CAUTION Changing any of the modem's settings may result in communication problems. After changing the settings, try the modem locally before installing it at a remote location. To speed problem resolution when contacting Campbell Scientific for support, please inform us of any modem setting changes that have been made.

A.1 DIP Switch Settings

The following COM220 settings are changed by opening or closing DIP switches:

1)Communication mode, either Synchronous Device Communication (SDC) or Modem Enable (ME)

2)ME baud-rate

3)PakBus ready.

To change DIP switch settings, the outer cover must first be removed by unscrewing and removing the five Philips head screws on the cover.

IMPORTANT It is necessary to cycle power to the COM220 for changes to the DIP switch settings to take effect. This is done by removing the 9 pin connector for about 5 seconds. As with other devices, if you leave the power off for too short a time, you may get unexpected results.

DIP Switches 1 and 2: SDC or Modem Enable

The COM220 supports Synchronous Device Communication (SDC) and Modem Enable (ME) communication. Switch 1 selects between SDC and ME. If switch 1 is open, ME mode is selected. If switch 1 is closed and switch 2 is open (default), SDC7 is selected. If both switch 1 and 2 are closed, SDC8 is selected. SDC is not supported by non-Pakbus operating systems (e.g., CR10X, CR23X, CR7, CR510). Hence, to connect with these older dataloggers, switch 1 must be open (i.e., Modem Enable mode selected).

DIP Switches 3 and 4: ME Baud-rates

DIP switches 3 and 4 only have effect when the COM220 is in Modem Enable mode. If the COM220 is in ME mode, switches 3 and 4 select the baud-rate setting between the COM220 and the datalogger as follows:

A-1