Measurement Computing Extender 488HS Rev.2.0 - Manual (Page 5)

Section 1 Introduction
1.1
Introduction
1.1 Description
The Extender488/HS High Speed IEEE 488 Bus Extender enables IEEE
488 devices to be controlled at a distance of up to 1,000 meters from a host
computer. The Extender488/HS overcomes the limit imposed by the IEEE 488
specification of 2 meters between any two devices. In addition, the
Extender488/HS Bus Extender allows up to 27 devices to be on the bus (plus the
controller and the two Extender488/HS Bus Extenders), versus the 14 device limit
imposed by the IEEE standard.
Two bus extenders are required to perform bus extension. The bus
connected to the host computer, or controller, is the "local" bus. The bus to which
control is extended is the "remote" bus. One Extender488/HS Bus Extender is
required on each bus to accomplish IEEE bus extension.
Communication between bus extenders is accomplished with parallel data
transmission, using RS-422 data drivers and receivers within the Extender488/HS
Bus Extender. This differential parallel data format provides high noise immunity,
high speed, and long-distance capability using a special cable.
Operation of the Extender488/HS Bus Extender is completely transparent to
the system. The controller can access both local and remote devices in exactly the
same manner.
IEEE
Devices
IEEE
IEEE
Devices
IEEE
IEEE
Controller Extender488 / HS
Extender488/HS
High-Speed
Parallel Link
Up to
1000 meters
Up to
14 IEEE
Devices
Up to
13 IEEE
Devices