IBM Series 1 User Manual page 125

other output lines available are:
•
ElA data terminal ready
On=±12 volts installed
• Solid state switch/TTL write control
• Solid state switch/TTL read control
Data bytes are transmi"tted across the adapter/device
interface serially by bit with the least significant hit
being transmitted first. An 11-bit start/stop frame is used
for synchronization of each byte. The bit rate is
selectable on the card by jumper pins. The following bit
rates are available:
50
75
100
110
150
200
300
600
1200
2400
4800
9600
The teletypewriter adapter feature is code transparent and
all 256 binary combinations can be transmitted and received.
The data exchange over the interface is not checked for
parity or device-dependent control characters. The adapter
can be configured to perform initial program load (IPt).
Data transfer between the adapter and the processor is
by byte using direct program control (DPe) commands;
however, during 1PL the transfer is by byte using cycle
steal.
The teletypewriter adapter feature is packaged on a
single circuit card that plugs into the backpanel of the
processor or the I/O expansion unit. The backpanels on
these units distribute the I/O channel signal lines to the
I/O feature card sockets. Pover is obtained from the
backpanel through card connector pins except when ±12 volts
are required as explained in the following section.
4-2 GA34-003J
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