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- > 3) My Pro380 cable (bcc03-o6) won't work with RB, what's wrong ??
- > The pin orders seemed to be quite the same.
-
- The Rainbow uses a BCC17 cable with the VR241 color monitor, NOT the BCC03 cable
- used by the Professional, DECmate and VT241 terminal. -- Here in the United
- States, Digital Equipment Corporation (DEC) is selling the BCC17-6 cable for $56
- US.
-
- BCC03 and BCC17 cables
- ======================
- The following data was extracted from the PDP-11 Systems And Options Catalog,
- October - December 1984 (DEC part number ED-26049-41), page 4-19.
-
- The cables consist of three 30 AWG coax cables and four 20-AWG stranded
- conductors with a 38 AWG tinned copper braid shield. The connectors are:
-
- P1 = 15 position D subminiature
- P2 = keyboard plug
- P3 = "B" BNC
- P4 = "G" BNC
- P5 = "R" BNC
-
- The wiring is:
-
- P1-1 -- P3 coax shield
- P1-2 -- P4 coax shield
- P1-3 -- P5 coax shield
- P1-4 -- --------------
- P1-5 -- P1-13 jumper
- P1-6 -- P2-3 conductor
- P1-7 -- --------------
- P1-8 -- P2-2 conductor
- P1-9 -- P3 coax center
- P1-10 -- P4 coax center in BCC03 only -- nothing in BCC17
- P1-11 -- P5 coax center
- P1-12 -- P4 coax center in BCC17 only -- nothing in BCC03
- P1-13 -- P1-5 jumper
- P1-14 -- P2-1 conductor
- P1-15 -- P2-4 conductor
-
-
- Rainbow keyboard / monitor connector (J3)
- =========================================
- The following pin assignments for the Rainbow keyboard/monitor connector were
- extracted from "PC100 Mother Board" skematic (DEC drawing size D, code CS,
- number 5415486-0-1, revision E) which is included in the "PC100 Field Maintenace
- Print Set (DEC part number MP-01491-00). The assignments are also listed in
- the Rainbow 100 Technical Manual (DEC part number EK-PC100-TM-001), table 3-6 on
- page 3-22 except that table shows the keyboard data flowing in directions
- opposite that shown on the skematic and listed below.
-
- The BCC02 monochrome cable wiring was obtained by inspecting that cable. BCC03
- and BCC17 cable wiring was from the source listed above.
-
- BCC02 BCC03 BCC17 Possible
- Rainbow Pin Mono Color Color Dual Monitor
- ======= === ===== ===== ===== ============
- Red shield ground ------- 1 ----- X X Color
- Green shield ground ----- 2 ----- X X Color
- Blue shield ground ------ 3 ----- X X Color
- Mono shield ground ------ 4 X ----- ----- Monochrome
- Ground ------------------ 5 X jumper jumper Monochrome
- Ground ------------------ 6 X X X Keyboard
- +12 volts --------------- 7 X ----- ----- Monochrome
- +12 volts --------------- 8 X X X Keyboard
- Blue video -------------- 9 ----- X X Color
- Green video ------------- 10 ----- X ----- Color
- Red video --------------- 11 ----- X X Color
- Mono video -------------- 12 X ----- X Monochrome
- -- not used ------------- 13 ----- jumper jumper -----
- Data from keyboard to CPU 14 X X X Keyboard
- Data from CPU to keyboard 15 X X X Keyboard
-
-
- Conclusion
- ==========
- Comparison of the above data suggests that when the graphics board is in a
- Rainbow, the BCC03 cable should route the color graphics signals to the VR241
- monitor. However, the monochrome signal generated on the Rainbow's motherboard
- will NOT be capable of being displayed with the BCC03 cable.
-
- As indicated in the "Rainbow Color/Graphics Option Programmer's Reference
- Guide" (DEC part number AA-AE36A-TV), the Rainbow can support three different
- monitor configurations: (1) monochrome monitor only, (2) color monitor only, and
- (3) both monochrome and color monitors. Each of the single monitor
- configurations presents a problem, that is how to get graphics video data to the
- monochrome monitor, and how to get motherboard video data to the color monitor.
- DEC solved these problems with a electronic switch on the motherboard. That
- switch is controlled by bit 2 of port 0A hexidecimal. Setting that bit to 0
- places motherboard video data on pin 12 of the BCC02 / BCC17 cable. In
- contrast, setting the bit to 1 puts graphics option "green" data on that pin.
-
- To my knowledge, DEC never sold a cable to support the Rainbow's dual monitor
- configuration. However, some people have built such a cable.
-
- (Note: The above data suggests a Professional or DECmate, when equipped with
- its graphics option and an appropriate cable, may also be capable of supporting
- a dual monitor configuration.)
-
-
- Carl C. Hoff
- choff@cs.wrigth.edu
-