IBM 1 Series - Relationship to Other Features; Application Summary

Relationship to Other Features
The communications power feature (#2010) furnishes +12 volts and is a
prerequisite for the teletypewriter adapter feature if the attached device is
connected to either the nonisolated current loop interface or the
EIA-voltage-level interface. The only exception is when the teletypewriter
adapter is plugged into a 4953-A processor, where +12 volts is standard
on the backpanel.
The communications power feature is not a prerequisite for the
teletypewriter adapter if the attached device is connected to either the
isolated current loop interface or the TTL-voltage-level interface. When
the attached device is connected to the isolated current loop interface, the
user must supply power to drive the transmit and receive loops. When the
attached device is connected to the TTL interface, normal logic levels
presented on the teletypewriter adapter card are used to drive the transmit
and receive loops.
The teletypewriter adapter card can be plugged into any I/O position that
has +5 volts available at the card slot on the 4955 or 4953 card files or
the I/O expansion unit card file. Refer to the prerequisite publications
listed in the Preface of this manual.
The A-slot provides only +5 volts (no +12 volts); therefore, the TTY
card can be plugged into the A-slot only if the attached device is
connected to either the TTL or isolated current loop interfaces.
Application Summary
The teletypewriter adapter is a device adapter designed to attach OEM
devices that operate as start-stop devices in full-duplex mode over a
four-wire interface (one pair of wires to transmit data, one pair of wires to
receive data). Data can be transferred in current loop mode, or as either
EIA or TTL signal levels.
The following is a list of different types of devices commercially available
that
can be attached to this interface:
e« Printer-keyboards
« Keyboard-display
e Keyboard-display-printer
e Printers
e Tape cassettes
e Tape
e Card readers
e Badge readers
e Plotters
The preceding devices can be attached if the interrupt mask time of the
program support system used does not preclude operation at the bit rate
required by the attached device.
4-4 GA34-0033