IBM 3270 Manual page 30

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3274 Device Cables
The device cables are the coaxial cables that connect the 3274 to its
attached display stations and printers either directly or via the IBM 3299
Terminal Multiplexer. These cables should be procured and installed before
the delivery of the 3274 and of the units that will be attached to the 3274.
Your personnel (or contractor) will connect these cables to the 3274 and to
the attached terminals.
Note: If you are replacing a 3271 or a 3272 with a 327 4, you can use the
existing device cables between the 3271/3272 and the attached units.
However, the 3271 or 3272 device cables must be connected/disconnected by
an IBM service representative, because the 3271 and 3272 and the attached
units do not have customer access areas. It is recommended that, before the
IBM service representative disconnects these cables, you have the cables
marked as described below.
To reduce delays associated with connecting these cables to the 327 4, it is
recommended that each cable be marked at both ends to identify:
• The 3274 connector panel type (Category A panels or Category B
panels) and the 3274 port (0 to 31) to which it is to be connected
• The unit type of the terminal to be attached.
For additional information concerning device cables, refer to IBM 3270
Information Display System: Installation Manual-Physical Planning,
GA27-2787.
IBM 3299 Terminal Multiplexer
The IBM 3299 Terminal Multiplexer provides improved flexibility in the
installation of a 3270 Information Display System by reducing the amount
of coaxial cabling required in an installation.
IBM 3270 Information Display System terminals are usually connected to
the 3274 Control Unit by coaxial cables. In some installations, available
space for these cables runs out as the number of terminals installed grows.
The 3299 attaches up to eight terminals. A single cable is used between the
3299 and the·3274 Control Unit, thus saving significant amounts of coaxial
cable.
The 3299 will be of interest primarily to customers installing newly
acquired 3270 systems, expanding existing systems, or relocating large
numbers of 3270 terminals. The 3299 will normally be installed at about the
same time that coaxial cabling is installed.
For details about the 3299, see IBM 3270 Information Display System: IBM
3299 Terminal Multiplexer Product Information, G520-4216.
Chapter 1. Planning Your Installation
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