Page of GC20-1801-10 As Updated April 1, 1981 by TNL GN25-0837 3270s Cluster and standalone control units are supported for remote 3270s. The IBM 3271 Control unit Model 2, and IBK 3274 Control Unit Kodels 1B
and 1C support clusters of up to 32 display stations and/or printers.
The IBM 3276 Control unit Display Station Models 2, 3, and 4 support
clusters of up to 8 display stations and/or printers. The IBK 3275
Display station, Model 2, is the standalone 3270 device that can be
remotely attached.
Note: The 3276, with a minimum configuration can also be considered a standalone 3270 device.
The following devices are supported when attached to the 3271 control
unit: • IBM 3277 Display Station, Model 2 • IBM 3284 printer, Model 2 • IBM 3286 Printer, Model 2 • IBM 3287 printer, 1 and '\ L • IBM 3288 Line Printer, Model 2
Note: The 3271/3272 Attachment Feature #8330 is a prerequisite when the rBM 3287 printer is attached to the 3271 control unit.
The following devices are supported when attached to the 3274 Control Unit Model 1C: • IBM 3277 Display station Model 2 • IBM 3278 Display Station Model 2, 3 and 41 • IBM 3284 Printer Model 2 • IBM 3286 Printer Model 2 • IBM 3287 Printer Models 1 and 2 • IBM 3289 printer Models 1 and 2
The following devices can be attached to the 3276 Control Unit Display station Models 2, 3, and 4: • IBM 3278 Display Station, Models 2, 3, and 41 • IBM 3287 printer, Models 1 and 2 • IBM 3289 printer, Models 1 and 2
The IBM 3275 Display Station, Model 2, is a standalone control unit
and display station. IOU can attach the IBM 3284 Printer, Kodel 3, to
the 3275. In addition, you can attach the IBM 3286 Printer, Model 3, to
the 3275 if RPQ MB4317 is installed. With the 3275 Dial Feature you can connect the 3275 to a computer over switched lines by using a
western Electric2 or equivalent data set. The 3275 Dial Feature does
not support full screen read/wr it e.
System Generation Requirements for Remotely Attached Display Systems When you generate VM/370 you must code the appropriate CLUSTER, TERMINAL, and RDEVICE macros and assemble them as part of the DHKRIO (real I/O configuration) file. Then, after the DMKRIO file assembles
successfully, you must make a list of the resource identification codes
of all the remote 3270 lines and terminals. Give the list to the
operations group at your installation; the members of that group need
this information when they issue the CP commands that control the
operation of remote 3270 lines and devices. IModels 3 and 4 default to the 1920 character screen size and are
functionally equivalent to the Model 2.
2Trademark of Western Electric Co.
Part 1. Planning for System Generation 53

A pr 1. I, I ::r 0 , 3270s THE CLUSTER MACRO Code one CLUSTER macro for each 3271 and 3274 control unit Model 1C,
each 3276 control unit display station, and each 3275 display station. Only a maximum of 16 CLUSTER macros is allowed. Each CLUSTER macro must
have a unique label. The CLUSTER macro is described in the "preparing
the Real I/O Configuration File section of "Part 2. Defining Your VM/370 System." THE TERMINAL MACRO Code one TERMINAL macro for each display station and printer that is
attached to the clustered 3271.
Code one TERMINAL macro for each display station and printer that is attached to 3274 control unit, 1C. For a 32
70 control unit Model 1C, the TERMINAL macros for 3278s, 3287s on a Type A
adapter, and 3289s must precede the TERMINAL macros for 3277s, 3284s,
3286s, 3287 on a Type B adapt er and 3288s.
Code one TERhINAL macro for each display station and printer that is
attached to a clustered 3276. Since the 3276 contains one integral
display unit, code one TERMINAL macro for the 3276 as a 3277. Code each
3278 attached to the 3276 as a 3277, and each 3287 attached to the 3276
as a 3284 or 3286. Code each 3289 as a 3288.
Code one TERMINAL macro for the 3275 display station. If a 3284 or
3286 printer is attached to the 3275, code MODEL=3 on the TERMINAL
macro. The TERMINAL macro is described in the "Preparing the Real 1/0 Configuration File (DMKRIO)" section of "Part 2. Defininq Your VM/370 System." THE RDEVICE MACRO Code one RDEVICE macro for each binary synchronous line used for remota 3270s (code one RDEVICE macro for each CLUSTER macro you code) • A
maximum of 16 RDEVICE macros for lines to support remote 3270s is
allowed.
The RDEVICE macro is described in Part 2. However, the format of the RDEVICE macro for the binary synchronous line and transmission control
unit for remote 3270s is included here to help you code the macro
correctly. The format of an BDEVICE macro for a communication line that
supports remote 3270s is:
54 IBM VM/370 Planning and System Generation Guide