The SN75LBC771 and SN75LBC776 GeoPort transceivers are designed for 9-pin Universal Network Bus applications. Both transceivers permit data transfer rates of up to 4 Mbps utilizing the GeoPort serial interface standard. This allows PC users to easily add telecommunications features requiring direct connections to high speed digital telephone/PBX systems, serial port interfaces and ordinary analog telephone lines.
The SN75LBC776 requires a single +5 V supply and generates its own negative supply using small 0.1 µF charge pump capacitors. The 'LBC776 provides a clear system cost advantage by reducing board space and external elements. For systems that already have a ±5 V supply, the SN75LBC771 is an even lower cost alternative.
Compared to other devices currently available, the 'LBC771 and the 'LBC776 are twice as fast, operating at up to 4 Mbps. This increased data rate supports isochronous, or "real time" data flow for applications such as video conferencing and voice/data transfers. In addition, both devices consume 1/10th the power of comparable (35 mW typ.) bipolar devices, and provide 10 kV of ESD protection. A power down mode further reduces power consumption to 165 µW (typ).
The GeoPort serial interface standard provides a simple, cross-platform solution allowing high-speed digital connections to telecommunications networks operating at ISDN and T1 data rates. It is supported by multiple PC and peripheral vendors, and it is backward compatible to AppleTalk™, LocalTalk™ and RS-232.
Both devices are available in 20-pin SOIC packages and are characterized
for operation from 0° to 70°C.
Vol 16, April, 1996
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