Difference between revisions of "DB11-A Bus Repeater"
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| − | The '''DB11-A Bus Repeater''' allows a [[UNIBUS]] to double the number of [[peripheral]]s connected to the [[bus]] (in terms of the combined [[analog]] load). It [[terminator|terminates]] the first section of the bus, and active [[digital]] logic repeats all the | + | The '''DB11-A Bus Repeater''' allows a [[UNIBUS]] to double the number of [[peripheral]]s connected to the [[bus]] (in terms of the combined [[analog]] load). |
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| + | It [[terminator|terminates]] (in analog terms) the first section of the bus, and active [[digital]] [[logic]] repeats all the [[signal]]s though onto the second section (or from the second back to the first, when required); the two sections are thus logically connected, but not in purely analog terms. | ||
It consists of a custom [[system unit]] [[backplane]], holding a number of smaller [[FLIP CHIP]]s; mostly [[DEC card form factor|singles]] (see table below), with one dual (M7213). | It consists of a custom [[system unit]] [[backplane]], holding a number of smaller [[FLIP CHIP]]s; mostly [[DEC card form factor|singles]] (see table below), with one dual (M7213). | ||
Revision as of 22:47, 24 December 2018
The DB11-A Bus Repeater allows a UNIBUS to double the number of peripherals connected to the bus (in terms of the combined analog load).
It terminates (in analog terms) the first section of the bus, and active digital logic repeats all the signals though onto the second section (or from the second back to the first, when required); the two sections are thus logically connected, but not in purely analog terms.
It consists of a custom system unit backplane, holding a number of smaller FLIP CHIPs; mostly singles (see table below), with one dual (M7213).
| Type | Count | Function |
|---|---|---|
| M783 | 1 | Bus driver |
| M784 | 1 | Bus receiver |
| M785 | 4 | Bus transceiver |
| M7212 | 3 | Address buffer |
| M7213 | 1 | Buffer master |
| M7248 | 1 | BBSY repeater |
| M930 | 2 | UNIBUS terminator |
Board locations (as seen from the board insertion side of the backplane, not the wire-wrap pin side, as is common in DEC documentation) are:
| Connector | ||||||
|---|---|---|---|---|---|---|
| Slot | A | B | C | D | E | F |
| 1 | UNIBUS A In | M7248 | M7212 | M7212 | M7212 | |
| 2 | UNIBUS A termination | Unused | M784 | M783 | ||
| 3 | Power | Unused | M7213 | M785 | M785 | |
| 4 | UNIBUS B Out | UNIBUS B termination | M785 | M785 | ||
