When planning an MBC-1 installation, common questions are "how many displays can be connected?" and "how far from the MBC-1 can they be?". There is no easy answer to these questions. We have tested a single Beta-Brite at 1000 feet with Belden 9451 cable which is well beyond the 50 feet maximum of the original RS-232 spec. But, of course, your milage may vary.

Cable quality is a factor at longer distances and when multiple displays are connected to a single MBC-1. Use the highest quality cable that is cost effective for the job for best results. Environmental noise is also a factor. Shielded, twisted pair cable usually works better in noisy conditions.

RS-232 signals can be boosted if signal strength is a problem. In fact, there are "short-haul modems" that can extend RS-232 signals for a mile or more but these can be expensive and are probably overkill for a typical MBC-1 installation. A solution that is cost-effective and considerably more practical is a simple RS-232 extender device. One such device is available from B&B Electronics, model 232LB9R (9 pin D connections) or model 232LB2 (25 pin D connections).

This type of extender device is installed inline many feet away from the MBC-1, not immediately next to it. It simply receives and repeats the data so it is transparent to the MBC-1 and the display(s). Again, there is no hard rule for how much more distance an extender will allow. It depends on the repeater, the cable and the environment.