Applies To:
  • CitectSCADA 3.xx, 4.xx, 5.xx

The Conitel protocol by Leeds and Northrup is used to communicate to a number of different RTUs (Remote terminal units). How do I interface Citect to RTUs with the Conitel protocol? 

The Conitel protocol has the following attributes:
  • bit-oriented
  • master-slave
  • multi-drop capable
  • half-duplex

A side effect of being bit-oriented is that the protocol cannot be used easily with standard serial ports on a computer, as the UARTs do no handle bit oriented protocols but rather byte oriented protocols. As a result, any solution would use non-standard equipment. Ci Technologies suggested method of interfacing using the Conitel protocol is to use a protocol converter. These converters convert the Conitel protocol into other well-defined protocols such as Modbus.

Conitel has a number of different variations including Conitel 2010, Conitel 2020, and Conitel 2025.

The following are some contacts for Conitel capable protocol converters:

- Miille Applied Research Company, Inc., PO Box 87634, Houston, Texas 77287, Ph: +1 713 472 6272, Fax: +1 713 472 0318, Web:, e-mail: