User manual

Connect Tech Xtreme/104 Plus, PCI-104 and PCI/104 Express Family User Manual
Revision 0.08
17
Electrical Interfaces Xtreme/104 Plus and Express (RS-
232/422/485 and RS-423 Models)
RS-232 Electrical Interface
This is the default setting for the interface selectable Xtreme/104-Plus and Xtreme/104-Plus
Opto. To operate a port in RS-232 mode, no jumpers are set on the corresponding jumper block.
RS-422/485 Electrical Interface
Xtreme/104 Express, Xtreme/104-Plus and Xtreme/104-Plus Opto RS-232/422/485 adapters
support three modes of RS-422/485 communication, as outlined below. (See Figure 8 to see
examples of jumper settings.)
Full Duplex 4-Wire Mode
In this mode, TxD+/- and RxD+/- are being driven to a known level all the time. This mode is
typically used in point-to-point situations much like RS-232.
Half Duplex 2-Wire Mode
In Half Duplex mode the TxD+/- line driver is enabled only when data is transmitted, whereas,
the RxD+/- is disabled when data is being transmitted. This mode is typically used in either
point-to-point 2-wire connections or in multi-drop 2-wire bus connections. In the Windows
Operating system, this mode requires software setup in Control Panel – System – Hardware – Device
Manager – Ports – CTI PCI UART. Click on Advanced under Port Settings after the driver is installed.
Multi-drop 4-Wire Mode
In this mode the TxD+/- line driver is enabled only when data is transmitted and RxD+/- is
enabled all of the time. This mode is typically used in multi-drop 4-wire connections. This
mode requires software setup in Control Panel – System Properties – Hardware - Device Manager – Ports
– CTI PCI UART. Click on Advanced under Port Settings. (See Half Duplex Mode).
Line Bias/Termination
The RS-422/485 transceivers, both transmit and receive are optionally biased to produce a line
level mark condition through jumper selectable resistors. These options are typically used in
multi-drop 4-wire connections.