IBM 1 Series Manual page 130

Generally, the most-significant bit of the selection is the highest of a
group. Four groups are provided. From top to bottom, facing the installed
card, they are:
¢ Input selection, binary coded, most-significant bit to least-significant
bit (3).
e Bit-rate selection, binary coded, most-significant bit to least-significant
bit (4).
e Device address, most-significant hex digit (4) and least-significant hex
digit (4).
e IPL selections, primary and secondary (2).
e Reserved (2).
Jumpersignificance is as follows:
e Input selection—jumperinstalled means that the appropriate bit of the
decode = logical 1. The decodeis as follows:
Input Input
MSB LSB selected interpretation
0 0 0 Contact sense Closed=data mark*
0 0 1 TTL Minus=data mark
0 1 0 EIA Minus=data mark
0 1 1 Internal True data out
1 0 O Contact sense Open=data mark
1 0 1 TTL Plus=data mark
1 1 O EIA Plus=data mark
1 1 1 Internal True data out
*The contact sense input, closed=data mark, is the no-jumper default selection.
e« Bit-rate selection—jumperinstalled means that the appropriate bit of
the decode = logical 1. The decodeis as follows:
Input
MSB LSB interpretation
0 0 0 0 110 bps*
0 0 0 1 Reserved
0 0 1 0 Reserved
0 0 1 1 Reserved
0 1 O 0 50 bps
0 1 O 1 100 bps
0 1 1 0 200 bps
0 1 1 1 Reserved
1 0 0 0 75 bps
1 0 0 1 150 bps
1 0 1 0 300 bps
] 0 | 1 600 bps
1 1 O 0 1200 bps
1 1 O 1 2400 bps
1 1 J 0 4800 bps
1 1 1 1 9600 bps
*110 bps is the no-jumper default bit-rate selection.
e Device address—jumperinstalled means that corresponding device
address bit =logical 1.
e JPilL—jumperinstalled means "'selected.'' If no jumpers areinstalled,
the teletypewriter adapter cannot perform IPL.
Teletypewriter Adapter Feature 4-25