User's Guide

8400B Plus Data Module User’s Guide 555-020-709
Issue 2
November 1996
S-Registers
C-25
Register: S21
Description: This S-register is used to store the status of bit-mapped
options as follows:
bit 0 — telephone jack options; set by &J command
(default = 0, see comment 1)
bit 1 — not used (always set to 0)
bit 2 — RTS/CTS options; set by &R command (default
= 0, see comment 1)
bits 3 and 4 — DTR options; value depends on
argument of DTR option command (default = 00, see
&D command)
bit 5 — DCD options; 0 = always on, 1 = EIA/TIA-574
standard (default = 0, see &C command)
bit 6 — DSR options; 0 = always on, 1 = EIA/TIA-574
standard (default = 0, see &S command)
bit 7 — long space disconnect options; (default = 0, set
by Y command, see comment 1)
Range of Values: Value may be 00 through FF hexadecimal;
factory-default settings produce a value of 00 (see
comment 2).
Storable: yes
Comments: 1. For the 8400B Plus Data Module, bits 0, 2, and 7
will be set by the appropriate command; however,
there will be no other effect.
2. Refer to the explanation of hexadecimal values
under the “Range of Values” heading on page C-4
.
Table C-1. Labels Used in S-Registers
Label Description
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