IBM Series 1 User Manual page 14

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The channel socket adapter feature consists of an IB~
printed circuit card that pluqs into the backpanel of the
IBM 4953 or 4955 Processor or 4959 I/O Expansion Unit. On
the top edqe of the IBM ~rinted circuit card is an industry
standard connector that accepts the user's I/O adapter card.
To power the user's circuits,
+5
volts dc at
2
amFeres is
available at the connector.
I/O ATTACHMENT FEATURES
The timeL feature card has two separately addressable 16-bit
timers. If desired, the user can supply his own time base
and
qatinq siqnals throuqh a connector
on
the top of the
card.
Each timer can generate periodic or aperiodic
interrupts with, or without, the external gate.
In addition to operatinq as an interval timer or pulse
counter, each timer can o~erat€ as a self-contained pulse
duration counter with end interrupt.
The teletypewriter adapter feature card provides a way of
attachinq a serial I/O device. This feature provides a
loqical subset of the
EIA
RS232-C interface. Full duplex
operation and initial program
load are
supported
by
the
adapter.
Attachment to a teletypewriter is
by
a dc current loop
(isolated or non-isolated).
Tva
other attachment options
are offered: (1) TTL compatible and (2) an ElA voltage level
inter face.
The integrated diqital I/O feature card contains:
• Two 16-point groups of non-isolated digital
input/process interrupt (Dl/PI)
• Two 16-point groups of non-isolated digital output (DO)
Each qroup of DI/PI and DO have a ready and a sync line
for synchronizing their operations with attached devices.
The diqital points for each group and their associated ready
and sync lines are available at three top-card connectors.
Introduction 1-3