I-Bus 4653 Telephone PBX Phone System Tower Computer 120/240V 50/60Hz ISA

I-Bus 4653 Telephone PBX Phone System Tower Computer 120/240V 50/60Hz ISA

The I-Bus 4653 is a compact tower computer purpose-built to serve as the processing core of a telephone PBX or computer telephony integration (CTI) system. It uses a PC-architecture chassis with ISA bus expansion slots designed to accept telephony line cards, voice processing boards, or other PBX-specific modules. I-Bus (also styled iBus) was a brand associated with embedded and telephony-application computers through the 1990s, producing purpose-built hardware for telecom OEMs and system integrators.

Specifications & What's Included

• Model: I-Bus 4653
• Form Factor: Tower
• Input Voltage: 120/240V AC (dual voltage, selector switch on rear)
• Current Draw: 3A @ 120V / 1.5A @ 240V
• Frequency: 50/60Hz
• Voltage Selector: Set to 115V (visible on rear panel)
• Expansion Slots: 4 × ISA expansion slot covers on rear panel
• AC Inlet: IEC C14 (standard 3-pin IEC power connector)
• Rear Cooling: Single exhaust fan
• Front Panel: Two buttons (green and gray/black)
• Included: Tower unit only — no expansion cards, cables, or accessories

Applications

The I-Bus 4653 was designed for use as the host computer in PBX telephone systems and CTI (computer telephony integration) platforms. In these deployments, telephony resource boards — such as voice processing cards, T1/E1 digital trunk cards, or analog station line cards — were installed into the ISA expansion slots, and the host computer ran PBX or call-processing software to manage call routing, voicemail, IVR, and related functions. This type of purpose-built telephony computer was a staple of business phone systems and call centers throughout the 1990s, when PC-based PBX platforms began displacing proprietary hardware switches. The dual-voltage power supply (120/240V) made the chassis suitable for both North American and international telephony deployments. Units like the 4653 are now primarily sought for legacy system maintenance, spare-parts inventory, or restoration of period-correct PBX installations.