Vector Graphic Bitstreamer II, Руководство пользователя

Страница: 36 / 54

Table 6 lists t.."1e RS-232C line available at each pad in Area H, I, and J.
The first set of RS-232C lines in the table apply if a standard 25-line
RS-232C cable is used. The second set of RS-232C lines apply if Vector
Graohic's Null Modem Cable is attached to the end of the Bitstreamer II
Serlal I/O cable, and then a standard RS-232C cable running to the
peripheral is attached to the other end of the Null l·lodem Cable. In t.~e
Null Modem Cable, several pairs of RS-232C lines are crossed, so that
RS-232C lines leaving the peripheral arrive at the Serial I/O cable on
different pins. The table also shows the three lines \vhich are connected to
+12 VDC on the board, through a pull up resistor.
RS-232C Line
(Standard cable
only is used)
RS-232C Line
(if Modem Adapter
Cable is used)
1
2 (+12 VOC)
3 (+12 VDC)
4 (+12 VOC)
5
6
Table 6 gives an idea of what the Null Modem Cable does, in addition to
the fact that it crosses lines 2 and 3. A complete description is as
follows: The Null Modem Cable has 25 lines, with a male DB-25 at each end.
The pairs of lines which are crossed are 2 and 3, 4 and 5, 6 and 20, and 8
and 19. All other lines are wired straight through.
If you are connecting an RS-232C handshaking line to some point on t.~e
board, refer to Table 5 to detennine \vhere in Area H, I, or J you can access
the line. If you need access to an RS-232C line which is not available
either in Area H, I, or J, or at one of the pins of sockets Jl, J2, or J3,
then you bring it to the board using a separate wire running from the D8-25
at the other end of the Serial I/O Cable.
To connect an RS-232C line directly to +12 VDC, simply install a jumper
on the back of the board from the desired pad in Area H, I, or J to the
closest end of the pUll up resister R9, Rl0, or Rll resp:ctively.
00
NOT
CONNECT IT DIRECTLY TO +12 VOC ON THE
BOAL1D.
Each res istor is found just
above its corresponding jumper area.
Remember that if you are connectinj a serial channel to a modem or other
Data Communications Equipment, and you are not using the Null :lodemCable,
you should disconnect RS-232C lines 5, 6, and 8 from the +12 VDC source on
the board, unless you are positive it poses no danger to the Data
Communications Equipment. You can cut these connections on the back of the