Sierra Video 507125 - Manual (Page 8)

Sierra Video Systems SmartLinx Bus Adapter busadap.doc
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At the SmartLinx data rate of 125,000 bps with 8 data bits, 1 stop bit, and no parity, the cable length is limited to
about 1000 feet. Termination resistors are required at both ends of the cable. One end is the bus adapter, where
termination resistors are built onto the board, and enabled by installing two jumpers:
Figure 6: Termination Resistor Jumpers
For the other end of the cable, a special termination resistor cable is required. However, it has been observed
that for shorter cable lengths, the other end should remain unterminated.
The bus adapter can be plugged into a single-module SmartLinx frame, and then connected to the other
SmartLinx frames via the SwitchCraft 3-pin connector. This is the recommended setup, because the single-module
frame can be placed near the host computer(s) to keep the EIA-232 cable lengths short. An alternative is available,
however. The bus adapter can be inserted into any SmartLinx frame of any size, and it will connect to the SmartLinx
bus using the 25-pin connector that plugs into the frame. In that case, the SwitchCraft connector is not used.
6. EEPROM Parameters
The bus adapter board contains a 128-byte EEPROM non-volatile memory. It is currently used by the software
to store the following data:
1. The 8-character user device name given to the bus adapter.
2. The two-digit SVS “dash number” supplied during factory setup of the board.
3. The 6-digit SVS serial number supplied during factory setup of the board.
4. A hardware version number string supplied during factory setup of the board.
Only the first item can be changed by the user.
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