Serial Devices; General Information About Serial Communication; Example Connection Diagrams - Lightware MODEX-OPTS-TX User Manual

4.2. Serial devices

4.2.1. General information about serial communication

There are two kind of devices in general serial communication from our aspect:
Data Terminal Equipment (DTE)
DTE is an end-instrument that converts user information into signals or reconverts received
signals. Typical DTE devices: computers, LCD touch panels, control systems.
Data Circuit-terminating Equipment (DCE)
DCE is device that sits between the DTE and a data transmission circuit. It also called data
communication equipment and data carrier equipment. Typical DCE devices: projectors,
industrial monitors and amplifiers.
Among others the pin assignment is different between DTE and DCE and different type of
serial cables have to be used between the serial devices.
Legend: RD=Received data; TD=Transmitted data
Serial cable types

4.2.2. Example connection diagrams

Following cases are examples; devices may have different receptacles and pin-outs.
Section 4. Installation
DTE
Pin2 RD
Pin3 TD
Table 4-1. Pin assignments and applicable serial cables
Straight serial cable
Straight pin-outs on both ends
Figure 4-2. Extending RS-232 between computer (DTE) and projector (DCE)
Figure 4-3. Extending RS-232 between computer (DTE) and computer (DTE)
DCE
TD DTE
RD DCE
Null-modem serial cable
Straight pin-out at the one end and
cross pin-out at the other end
(interchange lines of TX and RX)
Table 4-2. Serial cable types
MODEX-OPTS, MODEX-OPTM
User's Manual
DTE DCE
Null-modem Straight
Straight Null-modem
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