Tandy 1000 Owner's Manual

Appendix A
S16 Self-test toggle
The self-test mode forces the Modem to “talk to itself.” Apply value 1 to
S16 when you want to set the Modem to self-test mode. Using this feature,
you will be able to tell if the Modem is functioning correctly.
When the Modem is in self-test mode, the internal switches are selected such
that data transmitted from the computer is looped back to the receiver and
processed just as if it were in communications over the telephone lines. Keys
entered from the computer are echoed to the screen.
Since the Modem goes off-hook during the test,
be sure to disconnect the
wall jack phone line cord from the wall jack before executing a self-test.
To set the Modem for self-test mode, type:
AT S16= 1 D (ENTER) Self-test mode ON.
Originate mode.
AT
S16= 1 A (ENTER) Self-test mode ON.
Answer mode.
To set the Modem for self-test mode in answer mode, type:
35

Tandy 1000 Specifications

General

Processor	Intel 8088
Processor Speed	4.77 MHz
RAM	128 KB (expandable to 640 KB)
Operating System	MS-DOS 2.11
Manufacturer	Tandy Corporation
Release Year	1984
Storage	Single or double 5.25" floppy disk drive (360 KB), optional hard drive
Sound	Tandy 3-voice sound
Ports	Parallel, Serial
Graphics	CGA (Color Graphics Adapter)
Graphics Modes	320x200, 640x200