System information

Getting Started
2-20
MicroVAX 3100 Models 88/98 User Information
Connecting Peripherals to an Optional Asynchronous Port
There are two asynchronous communications options for Micro VAX 3100 88/98 systems:
• DHW42-BB -- Provides two eight-line data-line-only asynchronous ports
• DHW42-CB -- Provides two four-line asynchronous ports with modem control
If the system has the DHW42-BB asynchronous communications option installed, the
system has one or two eight-line data-only asynchronous ports. You can connect up to
eight peripherals to each of these ports using the H3104 harmonica.
To connect a peripheral to a DHW42-BB asynchronous port using the H3104 harmonica,
refer to Figure 2-16 and follow these steps:
1. Set the ON/OFF switch on the peripheral to the OFF (O) position.
2. Make sure that the 120-pin-to-2 x 36-pin cable supplied with your DHW42-BB is
installed. (Figure 2-16, Item 1)
3. Connect the straight connector of the BC16C-10 cable to one of the asynchronous
cable ports on the back of the system unit. (Figure 2-16, Item 2)
4. Close the bail lock loops on each side of the connector.
5. Connect the angled connector of the BC16C-10 cable to the H3104 harmonica.
6. Close the bail lock loops on each side of the connector.
7. Connect one end of a DEC423 cable to one of the eight MMJ ports on the harmonica.
8. Connect the other end of the DEC423 cable to a DEC423 port on the peripheral.
9. Set the ON/OFF switch on the peripheral to the ON (l) position.