Teletypewriter Adapter Electrical Characteristics - IBM Series 1 User Manual

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Sys!~ !~lateg Chacacteristics
Pow~.!: Failu~.
Any chacacter that is in the process of being
either transmitted or received during
a
power failure is
either lost or qarbled.
Power-on
reset is generated when the system is powered
back up. This siqnal resets all controls
and
registers in
the teletypewriter adapter except for the receive
serializer-deserializer register. This register is set to
all ones, which is the ASCII "rub out" character.
ErrQ'! Recovery. There is no checking of any kind between the
teletypewriter adapter and the user's device.
TELETYPEWRITER
ADAPTER ELECTRICAL CHARACTERISTICS
The teletypewriter adapter offers four different interfaces
or "ports" for connecting to user's devices. These
interfaces or ports are:
1 )
2)
3)
4)
Isolated current loop
Non-isolated current loop
EIA voltage level
TTL voltage level
The
teletypewriter adapter provides a 16-pin
(2x8)
top-card
connector for connecting the user's device.
A separate
pin or pair of pins on the top-card
connector provides the inputs and outputs for the four
different interfaces.
Input Circuits General Description
Refer to Figure 4-5. There are four basic types of receive
inputs: isolated contact sense, non-isolated contact sense,
TTL. and EIA RS232-C level.
Input options are selected:
• By
connecting to the appropriate pins, and
• By a 3-bit, coded jumper-pin selection on the card.
One bit of this code reverses the convention of the
inpu"t data mark. (See "Jumper Selections" in this
chapter for a detailed explanation of jumpering.)
Isolated Contact Sense. Two connector pins are available
forthe-signal input.--The isolated common may be strapped
to signal ground on the user's connector if desired in
certain applications. When the isolated contact sense input
Teletypewriter Adapter 4-17