Chapter
4.
System AHachment
This chapter contains information about the controller-to-host end of the
communications path.
Local Attachment
Locally, a
controller
is attached to a System/370-type processor through a selector,
multiplexer,
or
block
multiplexer
channel. The
controller
is attached by cables to
one of the
controller
positions on the host channel interface. From the host
computer, the
channel provides the
controller
with both the data
for
display
and
printing, and the
control information it needs to
direct
the operation of its attached
terminals. In
their
buffer storage, the
terminals
store the data from the
controller
for
display
or
printing. Each
display
station's buffer
permits
simultaneous
presentation of the display
image
and composition of a message from the
keyboard.
Locally attached controllers can be positioned as
far
as
122
meters
(400 feet) from
the system
channel, depending upon the system and channel configuration.
Locally attached controllers
are
the models 1
Land
11
L.
These models also attach
to the
IBM 3044 Fiber Optic Channel Extender Link, permitting the
controllers
to be
placed up to 2 kilometers (6600 feet) from the channel.
Remote Attachment
Remotely, the
controller
and the system channel can communicate in two ways:
(1)
through a channel-attached communication
controller
or
an integrated
communication adapter using
BSC protocol,
or
(2)
through a communication
controller
using BSC
or
SDLC protocol. The
controller
communicates with
intermediary
devices by means of communication facilities (data links), such as:
•
Modems
• Voice-grade channels
• Equivalent
facilities
such as telephone lines, microwaves,
or
satellites.
The
following
controllers
can be remotely attached using BSC protocol:
•
3174 Models
1R,
11R,
51R,
61R,
81R,
and
91R.
These
controllers
can be remotely attached using SDLC
or
X.25 protocols:
•
3174 Models
1R,
11R,
2R,
12R, 51R, 61R, 52R, 62R, 81R, 91R, 82R, and 92R.
Chapter
4.
System Attachment 4-1
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