IBM SY27-2300-1 2870 Multiplexer Chan FETOM Apr73 free download

File name SY27-2300-1_2870_Multiplexer_Chan_FETOM_Apr73.pdf

dr) ~5~ Field Engineering Theory of Operation Multiplexer Channel ( 60,000 and 70,000 Series) SY27-2300-1 PREFACE Because Engineering Changes may periodically obsolete portions of this manual, the latest level logic diagrams should be used as the final authority. This manual presents the fundamental concepts and operational principles for the 2870, 2870A, and 2870B :Multiplexer Channels. The machine type Note: References in this manual to COD (Channel suffix letters are determined by the system attach- Operation Diagram) and lOP (I/O Operation) ment and channel serial numbers. The channel diagrams relate to diagrams contained in Field designations are: Engineering Diagrams Manual, IBM 2870 Multi- plexer Channel (60,000 and 70,000 Series), System/360 models (not including the Model 195) SY27-2301. 2870 Ser. No. 60,000 and 60,002-69,999 Additionally, references to flowcharts (FC:XXX) 2870A Ser. No. 60,001 and 70,000 Series also appear throughout the text of this and other chapters; these relate to the autocharts contained System/370 models (including the System/360 in Volume 1 of the 2870 ALDIs. Model 195) 2870B 70,000 Series Manuals associated with this publication are: Field Engineering Diagrams Manual, IBM 2870 The information contained herein relates princi- Multiplexer Channel, SY27-2301. pally to the 2870A as a basis for data presentation. Field Engineering Maintenance Manual, IBM \\"hen the 2870 differs slightly from the description 2870 Multiplexer Channel, SY27-2302. provided for the 2870A series machines, the differ- ence is shown in parentheses with an asterisk (*). For example, the 2870 has eleven (*seven) levels of priority. It is assumed that the reader has a basic knowledge of the System/360 and System/370 funda- mentals of operation and standard I/O interface. Second Edition (April 1973) This is a reprint of SY27-2300-0 incorporating changes released in the following Technical Newsletters: SY22-691S (dated September 20, 1972) SY22-6926 (dated February 22, 1973) Changes are periodically made to the specifi