Black Box MX880A, Руководство пользователя

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CHAPTER 3: Configuration
3.1 Selecting the Number of Subchannels
1. Unscrew the two upper-cover screws located at the back of the unit and
slide the upper cover backward.
2. Locate the strap labeled “SELECT 6 OR 12 CHANNELS.”
3. For up to 6 channels with no controls, place the strap between the center
pin and the one marked “6.” For any other application, place the strap
between the center pin and the one marked “12.”
3.2 Setting Synchronous Data Rates
1. With the cover off the multiplexor, locate the three rotary data-rate
switches marked “CH.1,” “CH.2,” and “CH.3,” and the rate table located
to the left of these switches.
2. If you want to operate Channel 1, 2, or 3 in the synchronous mode, you
must rotate the channel switch(es) to the appropriate data-rate setting(s)
(refer to the rate table). If the synchronous mode isn’t needed, set the
three switches to positions 5, 6, or 7 (asynchronous mode).
3.3 Selecting the Transmit Clock (TC) Source (Synchronous Operation Only)
1. With the cover still off the multiplexor, locate the strap marked “TC
SOURCE.”
2. For normal synchronous operation (the Transmit-Clock signal is
generated internally), place the strap over the “IN” column of pins.
For loopback timing (the TC is synchronized to the Received-Clock signal
from the remote modem), place the strap over the “RX” column of pins.
If an External-Clock signal is provided by a DTE device on RS-232 Pin 24,
place the strap over the “EX” column of pins. Only Channel 1 can accept
an External Clock.