Computer Telephony Switch	The heart of the ST-510 is a rugged, fault tolerant industrial PC with DSP (digital signal processing) resources. The PC runs all the software routines required for the switch control and the services supported. The switch also assumes many functions normally supported by the SmarTrunk II controller, such as data base maintenance, subscriber validation and call record accounting.
Switch Rack & Power Supply	The ST-510 system components are mounted in a standard 19" rack panel with twelve slots to accommodate the switching components. Additional rack panels may be added to the system as required. Each rack panel includes a power supply that provides the required system voltages and supervises the overall system performance. A redundant 1+1 power supply is available for special applications
ST-422 Switch Board	All system switching and interface functions are performed by the ST-422 Switch Board. The ST-422 contains a micro-controller, an analog matrix switching structure, plus a highly versatile analog input/output with adjustable levels for each incoming or outgoing path. The ST-422 also has an RS-232 data port for digital interconnection with any external device, plus a powerful auxiliary port for future applications.

By use of an on-board DIP switch, the ST-422 can be easily configured for several different system functions:

• ST-853/858X controller switch gate
• Voice prompt/voice mail DSP switch gate
• PSTN/PBX switch gate · Roaming Bus switch gate
• Inter-site link switch gate
• Dispatch console switch gate