Page 22 of 39 RTE6701-OEM Integration Manual VC27U V1.03 DRAFT.doc
7.3
Cabling
The most critical connection for the VC27U OEM board is from J2 to the read head.
The read head cable (see
Appendix C – Read Head Cable
) has been designed to use a 0.1-inch pitch
insulation displacement (IDC) style connector with ribbon cable.
The signals on this cable consist of some high speed clock signals, power supplies and the sensitive analogue
signals returned from the camera in the read head carrying the picture of the document being scanned.
The pin-out of the cable has been designed to prevent the camera image being corrupted by the clock signals
when used with a ribbon cable. However some precautions are necessary to maximise the performance of the
read head.
Cable length should be limited to less than 6 inches / 150mm.
The read head will work with an unshielded cable but if the environment will contain high
levels of ambient electrical noise a shield can be used.
If a shield is fitted it should be connected to the power supply ground pin on the VC27U
board (the centre two pins of the 4 way power connector, J5).
3M can supply suitable shielded cables.
The use of multi-core cable with crimp terminal housings (such as the HE14 style
connector) is not recommended for the read head cable as the clock and camera
signals may run in close proximity and cause image corruption. This can cause
subtle problems such as misreads on certain types of documents.
