Appendix A Interface Guidelines; Rs-644 Digital Interface; Figure 12 Rs-644 Digital I/O Circuit - PerkinElmer RETICON LD3500 Series Instruction Manual

APPENDIX A Interface Guidelines
A.1 RS-644 Digital Interface
The LD3500 series digital signals (for both LVDS and Camera Link models) are
received and transmitted using balanced, differential circuits that comply with the
data transmission standards set forth in the EIA RS-644 specification.
All of the differential digital I/O signals on the MDR connectors are labeled (+)
or (-) to indicate polarity.
associated signal lines:
ON: When signal line (+) is more positive than (-).
OFF: When signal line (-) is more positive than (+)
This differential interface is necessary to assure proper camera operation and
optimum high speed data transmission in electrically "noisy" environments often
encountered in industrial applications. RS-644 differential line drivers and
receivers are available from various manufacturers. An example of a suitable
drivers is National Semiconductor DS90LV047 and an example of a suitable
receiver is National Semiconductor DS90LV048.
Figure 11 shows typical RS-644 input and output circuit configurations with the
type of circuit that should be used to transmit MCLK, LT, and LR and to receive
CCLK, LEN and CLT to and from the camera. It is also recommended to be used
on the Camera Link serial communications signals SerTFG and SerTC. The
following requirements apply:
1. All of the differential signal output pairs must be terminated at the
receiving end with a 100-120Ω resistor line to line.
2. The cable used for each differential signal should be twisted and shielded.
3. The shields should not be used for camera power ground return.
The following definitions apply to each pair of

Figure 12 RS-644 Digital I/O Circuit

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