Browse Prior Art Database

Channel Tap

IP.com Disclosure Number: IPCOM000107420D
Original Publication Date: 1992-Feb-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 3 page(s) / 89K

Publishing Venue

IBM

Related People

Carey, JJ: AUTHOR

Abstract

This article describes a passive method of attaching control units to a System 360/370 channel, provided that the control units meet the original equipment manufacturer's interface specification for the 360/370 system.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Channel Tap

       This article describes a passive method of attaching
control units to a System 360/370 channel, provided that the control
units meet the original equipment manufacturer's interface
specification for the 360/370 system.

      The IBM System/370* channel is a collection of high-speed
transmission lines that allow external control units to communicate
to the CPU.  Control unit attachment is done under very strict
guidelines to maintain the electrical integrity of the channel.
Thirty-nine signals are required for channel communication.
Thirty-seven of the signals use a "dot" method of attachment, and the
remaining two "daisy chain" through each attaching control unit (see
Fig. 1).

      Unterminated stubs over 6" in length are not permitted. This
means the physical attachment point to each channel conductor should
be less than 6" from the control unit's driver and receiver circuits.
Most control units solve this problem by locating their logic
circuits near the normal point of cable entry or by routing the
channel cables to an area that the circuits can be located and still
provide the mechanical stability for the four large serpentine
connectors and the bulky standard channel cables they terminate.

      CHANNEL TAP consists of a tap unit that performs the
translation from the coax-cable-bundle / 4 serpentine connector
transmission scheme, and a secondary transmission system that
provides a single connector interface to the attaching control unit.

      CHANNEL TAP uses four serpentine connectors to conform to the
physical interface of the standard channel.  The signals from the
four serpentines are funneled into two shielded miniature connectors
that provide the interface...