Tandy DCM-7 User manual
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OPERATION
MANUAL
Cat. No. 26-1394
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TERMS
AND
CONDITIONS
OF
SALE
AND
LICENSE
OF
TANDY
COMPUTER
EQUIPMENT
AND
SOFTWARE
PURCHASED
FROM
RADIO
SHACK
COMPANY-OWNED
COMPUTER
CENTERS,
RETAIL
STORES
AND
RADIO
SHACK
FRANCHISEES
OR
DEALERS
AT
THEIR
AUTHORIZED
LOCATIONS
LIMITED
WARRANTY
CUSTOMER
OBLIGATIONS
A.
CUSTOMER
assumes
full
responsibility
that
this
computer
hardware
purchased
(the
"Equipment"),
and.
any
copies
of
software
included
with
the
Equipment
or
licensed
separately
(the
"Software")
meets
the
specifications,
capacity,
capabilities,
versatility,
and
other
requiiements
of
CUSTOMER.
B.
CUSTOMER
assumes
full
responsibility
for
the
condition
and
effectiveness
of
the
operating
environment
in
which
the
Equipment
and
Software
are
to
function,
and
for
its
installation.
11.
LIMITED
WARRANTIES
AND
CONDITIONS
OF
SALE
A.
For
a
period
of
ninety
(90)
calendar
days
from
the
date
of
the
Radio
Shack
sales
document
received
upon
purchase
of
the
Equipment.
RADIO
SHACK
warrants
to
the
original
CUSTOMER
that
the
Equipment
and
the
medium
upon
which
the
Software
is
stored
is
free
from
manufacturing
defects.
This
warranty
Is
only
applicable
to
purchases
of
Tandy
Equipment
by
the
original
customer
from
Radio
Shack
company-owned
computer
canters,
retail
stores,
ana
Radio
Shack
franchisees
and
dealers
at
their
authorized
locations.
The
warranty
is
void
if
the
Equipment's
case
or
cabinet
has
been
opened,
or
if
the
Equipment
or
Software
has
been
subjected
to
improper
or
abnormal
use.
If
a
manufacturing
defect
is
discovered
during
the
stated
warranty
period,
the
defective
Equipment
must
be
returned
to
a
Radio
Shack
Computer
Center,
a
Radio
Shack
retail
store,
a
participating
Radio
Shack
franchisee
or
a
participating
Radio
Shack
dealer
for
repair,
along
with
a
copy
of
the
sales
document
or
lease
agreement.
The
original
CUSTOMER'S
sole
and
exclusive
remedy
in
the
event
of
a
defect
is
limited
to
the
correction
of
the
defect
by
repair,
replacement,
or
refund
of
the
purchase
price,
at
RADIO
SHACK'S
election
and
sole
expense.
RADIO
SHACK
has
no
obligation
to
replace
or
repair
expendable
items.
B.
RADIO
SHACK
makes
no
warranty
as
to
the
design,
capability,
capacity,
or
suitability
lo,r
use
of
the
Software,
except
as
provided
in
this
paragraph.
Software
is
licensed
on
an
"AS
IS"
basis,
without
warranty.
The
original
CUSTOMER'S
excl~sive
remedy,
in
the
event
of
a
Software
manufacturing
defect,
is
its
repair
or
replacement
within·
thirty
(30)
calendar
days
of
the
date
of
the
Radio
Shack
sales
document
received
upon
license
of
the
Software.
The
oefective
Software
shall
be
returned
to
a
Radio
Shack
Computer
Center,
a
Radio
Shack
retail
store,
a
participating
Radio
Shack
franchisee
or
Radio
Shack
dealer
along
with
the
sales
document.
C.
~~~~~~ti~;
g{~~de~at~~~e~~
~~hiinloA~e
01
Jgi~~c~.anchisee,
dealer
or
other
person
is
authorized
to
give
any
D.
EXCEPT
AS
P~OVIDED
HEREIN,
RADIO
SHACK
MAKES
NO
EXPRESS
WARRANTIES,
AND
ANY
IMPLIED
WARRANTY
OF
MERCHANTABILITY
OR
FITNESS
FOB
A
-PARTICULAR
PURPOSE
IS
LIMITED
IN
ITS
DURATION
TO
THE
DURATION
OF
THE
WRITTEN
LIMITED
WARRANTIES
SET
FORTH
HEREIN.
E.
Some
states
do
not
allow
limitations
on
how
long
an
impliea
Warranty
lasts~
so
the
above
limitation(s)
may
not
apply
to
CUSTOMER.
Ill.
LIMITATION
OF
LIABILITY
A.
EXCEPT
AS
PROVIDED
HEREIN,
RADIO
SHACK
SHALL
HAVE
NO
LIABILITY
OR
RESPONSIBILITY
TO
CUSTOMER
OR
ANY
OTHER
PERSON
OR
ENTITY
WITH
RESPECT
TO
ANY
LIABILITY,
LOSS
OR
DAMAGE
CAUSED
OR
ALLEGED
TO
BE
CAUSED
DIRECTLY
OR
INDIRECTLY
BY
"EQUIPMENT"
OR
"SOFTWARE"
SOLD,
LEASED,
LICENSED
OR
FURNISHED
BY
-RADIO
SHACK,
INCLUDING,
BUT
NOT
LIMITED
TO,
ANY
INTERRUPTION
OF
SERVICE,
LOSS
OF
BUSINESS
OR
ANTICIPATORY
PROFITS
OR
CONSEQUENTIAL
DAMAGES
RESULTING
FROM
THE
USE
OR
OPERATION
OF
THE
"EQUIPMENT"
OR
"SOFTWARE."
-IN
NO
EVENT
SHALL
RADIO
SHACK
BE
LIABLE
FOR
LOSS
OF
PROFITS,
OR
ANY
INDIRECT,
SPECIAL,
OR
CONSEQUENTIAL
DAMAGES
ARISING
OUT
OF
ANY
BREACH
OF
THIS
WARRANTY
OR
IN
ANY
MANNER
ARISING
OUT
OF-OR
CONNECTED
WITH
THE
SALE,
LEASE,
t:ICENSE,
USE
OR
ANTICIPATED
USE
OF
THE
"EQUIPMENT"
OR
"SOFTWARE."
- -
NOTWITHSTANDING
THE
ABOVE
LIMl'l'ATIONS
AND
WARRANTIES,
RADIO
SHACK'S
[[ABILITY
HEREUNDER
FOR
DAMAGES
INCURRED
BY
CUSTOMER
OR
OTHERS
SHALL
NOT
EXCEED
THE
AMOUNT
PAID
BY
CUSTOMER
FOR
THE
PARTICULAR
"EQUIPMENT"
OR
"SOFTWARE"
INVOLVED.
- -- -
B.
RADIO
SHACK
shall
not
be
nable
for
any
damages
caused
by
delay
in
delivering
or
furnishing
Equipment
and/or
Software.
C.
No
action
arising
out
of
any
claimed
breach
of
this
Warranty
or
t.ransactions
.under
this
Warranty
may
be
brought
more
than
two
(2)
·years
after
the
cause
of
action
has
accrued
or
more
than
four
(4)
years
after
the
date
of
the
Radio
Shack
sales
document
for
the
Equipment
or
Software,
whichever
first
occurs.
D.
Some
states
do
not
allow
the
limitation
or
exclusion
of.
incidental
or
consequential
damages,
so
the
above
limitation(s)
or
exclusion(s)
may
not
apply
to
CUSTOMER.
IV.
SOFTWARE
LICENSE
RADIO
SHACK
grants
to
CUSTOMER
a
non-exclusive,
paid-up
license
to
use
the
TANDY
Software
on
one
computer.
subject
to
the
following
provisions:
A.
Except
as
otherwise
provided
in
this
Software
License,
applicable
copyright
laws
shall
apply
to
the
Software.
B.
Title
to
the
medium
on
which
the
Software
is
recorded
(cassette
and/or
diskette)
or
stored
(ROM)
is
transferred
to
CUSTOMER,
but
not
title
to
the
Software.
C.
CUSTOMER
may
use
Software
on
a
multiuser
or
network
system
only
if
either,
the
Software
is
expressly
labeled
to
be
for
use
on
a
multiuser
or
network
system,
or
one
copy
of
.this
software
is
purchased
for
each
node
or
terminal
on
which
Software
is
to
be
used
simultaneously.
D.
CUSTOMER
shall
not
use,
make,
manufacture,
or
reproduce
copies
of
Software
except
tor
use
on
one
computer
and
as
is
specifically
provided
in
this
Software
License.
Customer
is
expressly
prohibited
from
disassembling
the
Software.
E.
CUSTOMER
is
permitted
to
make
additional
copies
of
the
Software
only
for
backup
or
archival
purposes
or
if
additional
copies
are.
required
in
the
operation
of
one
computer
with
the
Software,
but
only
to
the
extent
the
Software
allows
a
backup
copy
to
be
made.
However,
tor
TRSDOS
Software,
.CUSTOMER
is
permitted
to
make
a
limited
number
of
additional
copies
for
CUSTOMER'S
own
use.
F.
CUSTOMER
may
resell
or
distribute
unmodified
copies
of
the
Software
provided
CUSTOMER
has
purchased
one
copy
of
the
Software
for
each
one
sold
or
distributed.
The
provisions
of
this
Software
License
shall
also
be
applicable
to
third
parties
receiving
copies
of
the
Software
from
CUSTOMER.
G.
All
copyright
notices
shall
be
retained
on
all
copies
of
the
Software.
V.
APPLICABILITY
OF
WARRANTY
A.
The
terms
and
conditions
of
this
Warranty
are
applicable
as
between
RADIO
SHACK
and
CUSTOMER
to
either
a
sale
of
the
Equipment
and/or
Software
License
to
CUSTOMER
or
to
a
transaction
whereby
Radio
Shack
sells
or
conveys
such
Equipment
to
a
third
party
for
lease
to
CUSTOMER.
B.
The
limitations
of
liability
and
Warranty
provisions
herein
shall
inure
to
the
benefit
of
RADIO
SHACK,
the
author.
owner
and
or
licensor
of
the
Software
and
any
manufacturer
of
the
Equipment
sold
by
Radio
Shack.
VI.
STATE
LAW
RIGHTS
The
warranties
granted
herein
give
the
original
CUSTOMER
specific
legal
rights,
and
the
original
CUSTOMER
may
have
other
rights
which
vary
from
state
to
state.
8/85
The
FCC
Wants
You
to
Know
This
equipment
generates and uses radio
frequency
energy.
If
not
installed and used properly,
that
is in
strict
accordance
with
the
manufacturer's
instructions,
it
may cause interference
to
radio and television reception.
It has been
type
tested and found
to
comply
with
the
limits
for
a Class B
computing
device
in
accordance
with
the
specifications
in Subpart J
of
Part 15
of
FCC Rules,
which
are designed
to
provide reasonable
protection
against such
interference
in
a residential
installation.
However,
there
is no guarantee
that
interference
will
not
occur
in
.a
particular'
installation.
If
this
equipment
does cause interference
to
radio or television reception,
which
can be
determined
by
turning
the
equipment
off
and on, the user is encouraged
to
try
to
correct the in-
terference by one
or
more
of
the
following
measures:
• Reorient
the
receiving antenna
• Relocate the
computer
with
respect
to
the
receiver
• Move
the
computer
away from the receiver
• Plug
the
computer
into
a
different
outlet
so
that
computer
and receiver are on
different
branch
circuits.
Warning
This
equipment
has been
certified
to
comply
with
the
limits
for
a Class B
computing
device,
pursuant
to
Subpart
J
of
Part
15
of
FCC Rules. Only peripherals
(computer
input/ouput
devices,
terminals,
printers, etc.)
certified
to
comply
with
the Class B
limits
may be attached
to
this
computer.
Operation
with
non-certified peripherals is
likely
to
result in interference
to
radio and TV reception.
2/86
300-Bps Intelligent Modem
DCM-7
Operation Manual: .
© 1986 Tandy Corporation,
Fort
Worth,
Texas 76102 U.S.A.
All Rights Reserved.
Reproduction
or
use, without express written permission from Tandy Corpora-
tion,
of
any portion
of
this manual
is
prohibited. While reasonable efforts have
been taken in the preparation
of
this manual
to
assure its accuracy, Tandy
Corporation assumes no liability resulting
from
any errors
or
omissions in this
manual,
or
from
the use
of
the information contained herein.
Hayes ® is a registered trademark
of
Hayes Microcomputer Products, Inc.
XENIX®
is a registered trademark
of
Microsoft Corporation.
10
9 8 7 6 5 4 3 2 1
Contents
Introduction
...
...
..
....
..
...........................
..
.........
....
.....
...
....
·1
1· Description
of
the DCM-7
....
..........
.....
.....
..
...
.
......
. 3
Protocol (DIP) switches ........•............................................ 5
Communications protocol ......•.......•.•.....
.....................•.......
8
2 Tandy protocol mode operation ...........................
11
Manual v. automatic operation
...................•................•......
11
Originate v. answer mode
...............................•......•.....•.....
11
Sample programming sessions
..................................•..•.......
11
Manual mode ·operations ......•.....•............
...
.....•............•.....
14
Automatic mode operations ..•........•................
•.•
................•
15
Analog self-test mode
••....•...................•.•............•.•...........
17
Always auto-answer mode operation ..........................•.......•.
18
On-line abort conditions ..•.•.•....•.•...............•..........•...........
18
Result codes ...••..•....••.•...........•........•....•..........................
19
3 Hayes® protocol mode operation .........................
21
Command codes ...........•.
.•
....................•................•.........
21
Registers ...•.............•...........•..........••...............................
24
Result codes .....•.•.............•......•.•.•...........•.......................
26
Logons in MS-DOS operating systems
.......•..............•...........
26
Appendices
A Tandy protocol reference ....................................... 31
B Hayes protocol reference ........................................
39
Programming commands .
...
.......•....•.....•...............•.•.....•.....
39
Registers ...........•....•.•........•..•.........•.............•.•................
44
Data
line monitoring
.•....
~..................................................
48
C Connecting the DCM-7 ...........................................
49
Telephone connections .............•......................................•.
49
Computer connections .......................................................
51
Power source .•...•..•••..•.•.•••.•.••.............••...•..........•....••.....
51
Contents
D XENIX® operations ................................................. 53
E Troubleshooting ......................................................... 55
Analog loop self-test •••••.....•....•••..•.....•.•..•.......••....••.•.......• 55
Multi-line phone operation ••.........•.••......•...•....•...........•.•.... 56
F Specifications ..................................
~
........................... 57
Performance .....•.•.•....•.........•.....•.•..........••.......••.........•... 57
Physical/environmental •..•..•..••...............•...•........•.•..•....•... 57
G Schematic diagram ................................................... 59
Index
··············································································~··
61
Tables
1
DIP
Switch Settings in Tandy Protocol Mode ..............•......... 6
2
DIP
Switch Settings in Hayes Protocol Mode
....•...•...........•..•
8
3 Result Codes (Tandy) •.....•.•.•.•......•...
•.
•......
...
...•...•..•........... 19
4 Commands with Parameters (Hayes)
...........................•........
22
5 Basic Command Codes (Hayes)
.•......•............•.•.......•..........
23
6 Dialing and Answering Command Codes (Hayes)
...................
23
7 Registers (Hayes) .•......•.•.•.....•••.........•...••..
.......
..•.
.......•.
.•.
24
8 Result Codes (Hayes)-
.........•.•.••••...........•.•..•........•........•....
26
9 Programining Commands (Tandy)
...........•..•.....................•..
31
10 List Settings and Related Commands (Tandy) ..............•......... 36
11
Dialer Codes (Hayes)
.........................................................
40
12
Modem-to-Computer Cables ..............•.•.............•..•.•.•.........
51
13
Computer Option Boards .•...•.•...............•...................•.....•.
51
Introduction
With the Tandy direct-connect, 300-Bps Intelligent Modem DCM-7, your
computer or data terminal can communicate with other computers
or
termi-
nals using ordinary telephone lines.
The DCM-7 accepts data from a computer, converts the data into two-
frequency tones and then sends the tones over telephone lines
to
another
modem. Conversely, the DCM-7 accepts tones from telephone lines and
changes those tones into
data
that your computer understands.
This direct-connect, Bell 103-type modem
is
not only designed with standard
automatic dial, answer
and
disconnect features, but also a wide range
of
system configuration enhancements
as
well. Its microprocessing unit (MPU)
provides operation in both Tandy and Hayes protocol modes -each selec-
table
at
the flip
of
a
DIP
switch.
In the Hayes protocol mode, your Modem
is
AT-compatible and capable
of
running with Hayes software. Special command instructions and registers
in Hayes protocol allow you
to
program the DCM-7 from your computer
keyboard for the same operational modes used in Tandy protocol.
For example, you can set the DCM-7 for manual originate
or
manual answer
mode,
in
which you manually dial the telephone number or answer an
incoming call when you are contacting a remote computer.
Or
you can pro-
gram the DCM-7 for auto-originate or auto-answer mode and let the DCM-7
dial the telephone number
of
a remote computer or answer
an
incoming call.
In either Tandy
or
Hayes protocol, the DCM-7 can be programmed to
perform operations such
as
automatically seizing the telephone line after a
specified number
of
rings and automatically redialing a phone number when
communication
is
not established.
Another feature
of
the DCM-7
is
a built-in monitor speaker which enables
you to monitor audibly the dialing and data communication progress. The
situation
is
reported visually
on
your display with messages called results
codes.
Sample programming sessions are provided in each section
of
this manual
to help familiarize you with the various functions
of
the DCM-7 and to get
you started using your Modem
as
quickly
as
possible. After you have become
familiar with the manual and your Modem, the handy Quick Reference Card
should keep you "up-and-running!"
,l
·
....
Description
of
the DCM-7 1
When power
is
first applied, several
of
the indicators
on
the DCM-7's front
panel will light -depending
on
the status
of
the computer's protocol and
DIP switch settings. These 6 indicators show the Modem's internal and
ex-
ternal operation status.
G)
POWER
indicator lights when the power is ON.
@
POWER
switch turns the Modem
ON
or
OFF.
Be
sure.
to
turn
it OFF
when the Modem
is
not being used.
®
OFF
HOOK indicator lights when the Modem
is
ON
LINE (connected
to
the
phone line).
@ TERMINAL READY indicatorlights when the terminal
is
supplying the
DTR
(Data Terminal Ready) signal.
®
CARRIER
DETECT indicator lights when the Modem receives a carri-
er
tone
or
generates a "false" carrier. ·
® TRANSMIT DATA indicator flashes when the Modem
is
transmitting
data.
(j) RECEIVED DATA indicator flashes when the Modem
is
receiving
dat~.
CD
®
POWER IOFF HOOK I TERMINAL
READY
®
CARRIER
DETECT
®
ITRANSMIT I RECEIVED
DATA DATA
TANDY'
300
BPS
INTELLIGENT MODEM DCM-7
Figure 1.
Front
Panel View
3
Description
of
the DCM-7
CD
RS-232C standard DB-25
jack
connects the Modem to the RS-232C in-
terface
of
your computer.
@
PROTOCOL
(DIP) switches control the Modem's power-up condition.
@
PHONE
jack
connects the telephone to the Modem.
@
POWER
jack
connects the Modem to the
AC
power adapter.
® WALL
JACK
phoneline cord connects the Modem to the telephone line.
PHONE
CD
® © ®
Figure 2
..
Rear Panel View
Before you connect the DCM-7, first read the instructions in Appendix
C,
Connecting the DCM-7.
Be
sure to
turn
OFF
the power to the Modem
and
to
the computer! .
Figure 3. A Typical Connection
4
Chapter 1
Protocol (DIP) switches
DIP switches control the DCM-7's power-up condition. These switches must
be set before you turn the power ON.
First, you will have to decide whether you want to use the Modem in the
Tandy protocol mode or Hayes protocol
mode~
If
you are using Tandycom-
munications software, you will want to set it for Tandy protocol.
For
use
with Hayes communications software, set it to the Hayes protocol mode.
(Both
the
Tandy
1000
and 1200
and
3000 personal computers can be used
with either communications software.)
Tandy protocol
When you select Tandy protocol mode, set
DIP
Switch 7 to ON. This tells
the Modem to set other
DIP
switch functions as listed in Table
1.
Refer to
Figure 4 for the suggested switch settings in this mode (black portion shows
the switch position).
NO
FUNCTION~
m=;NO
FUNCTION
NO
FUNCTION~
~AUTO
ANSWER DISABLE
TRUE
CARRIER!
I HAYES PROTOCOL
TRUE
DTR
1 1 1 1
No
FUNCTION
l
1
~~~~~~11l~.
1~
01
2 3 4 5 G 7 8
N -
FORCED DTR J I
1111
I LNO FUNCTION
FORCED CARRIER TANDY PROTOCOL
NO FUNCTION..
..
. . .... AUTO ANSWER ENABLE
NO FUNCTION - . .
..
NO
FUNCTION
Figure 4.
DIP
Switch Settings in Tandy Protocol Mode
5
Description
of
the DCM-7
SW
2
3
4
5
6
Table 1.
DIP
Switch Settings in Tandy Protocol Mode
Position
ON
OFF
ON
OFF
Should be OFF
Should be OFF
Should be OFF
ON
Function
Forced
DTR
(Data Terminal Ready). Modem accepts
command from the local computer without a DTR
signal.
True DTR. Modem is OFF until it receives a true DTR
signal from the computer.
Forced carrier. Modem assumes forced carrier
detecf1> and disables the G command.
Forced/True carrier. Modem selects between forced
carrier detect and true carrier
detecf
2>according to
the G command input.
No function.
No function.
No function.
Auto-answer enable. Modem assumes auto-answer
upon power-up.
OFF Auto-answer disable. Modem assumes auto-originate
upon power-up.
7 Should be ON Tandy. Sets the Modem to Tandy protocol mode.
8 Should be OFF No function.
*
1)
Forced carrier detect ... Modem issues a forced carrier signal to the local com-
puter as soon
as
power is turned ON.
*2) True carrier detect ... Modem will be off until it receives true carrier from the
remote computer.
DIP
Switch 2 interlocks with
DIP
Switch 6 as follows:
i
ON
i
ON
Modem assumes auto-answer with forced carrier
detect.
Modem assumes auto-originate with forced car-
rier detect.
6
Chapter I
i
~
~
Modem assumes auto-answer with true carrier
ON detect at power-on. The true/forced carrier con-
2 6 dition can be changed with the G command.
i
~
~
Modem assumes auto-originate wlth forced car-
ON
rier detect at power-on. The true/forced carrier
2
€)
condition can be changed with the G command.
Hayes protocol
When you want to use your DCM-7 in Hayes protocol mode, position Switch
7to
OFF.
In this protocol mode, the remaining switches function differently
from those in Tandy protocol. Refer
to
Figure 5 for suggested switch
set-.
tings
in
Hayes protocol mode.
SEND
RESULT CODES
~COMMAND
ECHO
ON
NUMERIC
RESUL_
T
COD-
ES
-
11
JG-
--
AUTO.ANSWER ENABLE
TRUE
CARRIER~
jHAYES
PROTOCOL
TRUE DTR1 1 1
rNo
FUNCTION
11~~-
w~~w~~
1~
~1
2 3 4 5
€)
7 8
FORCED
ornJ
I
11
·
111
LNo
FUNCTION
FORCED
CARRIER~
TANDY PROTOCOL
VERBAL RESULT CODES - - . _- AUTO ANSWER DISABLE
NO
RESULT CODES
--
-_
- - - COMMAND ECHO OFF
Figure 5.
DIP
Switch Settings in Hayes Protocol Mode
7
Description
of
the DCM-7
Table 2.
DIP
Switch Settings
in
Hayes Protocol Mode
SW
•Position Function
ON
Forced
OTA.
OFF True
OTA.
2
ON
OFF
3
ON
OFF
4
ON
OFF
5
ON
OFF
6
ON
OFF
7 Should
be
OFF
8 Should
be
OFF
Forced carrier detect.
True carrier detect.
Displays verbal result codes.
Displays numeric result codes.
Result codes disabled. Disables Switch 3.
Result codes enabled. Enables Switch 3.
Command echo disable.
Command echo enable.
Auto-answer disable.
Auto-answer· enable.
Sets the Modem to Hayes protocol mode.
No
Function.
For
.easy operation, position Switch 5 to OFF
to
echo the command line.
Set Switch 4
to
OFF
and Switch 3 to
ON
to
send the verbal result codes
to
the screen.-
Communications protocol
The following criteria must be met before computer'-to-computer communi-
cation can·occur.
1.
Both
computers must have the same communications protocol:
300 bits/second (Bps)
Word length
(7
bits
or
8 bits)
Parity (even, odd
or
none)
Number
of
stop bits
(1
or
2 bits)
See your computer owner's manual for instructions
on
setting the com-
munications protocol.
2. One modem must be in ORIGinate mode and the other must be in
AN'"
Swer mode. Usually, when you call another computer, you should be
in ORIGinate mode. When you receive a call, you should be in ANSwer
mode.
8.
Chapter 1
The DCM-7 provides automatic and manual operations in both originate and
answer modes. When opened for programming by the wake-up
oi
attention
code sequence, it will automatically synchronize the speed rate, word length,
parity
and
stop-bit numbers (communications protocol)
of
your computer·
system.
Helpful Tip:
Whe,n
you use your
DCM-:-
7 for the first time
or
when you seem to be getting
. garbled data, use the self-test mode to help you find the cause
of
the problem.
Refer
to
the section
on
self-test in Appendix A, Tandy protocol reference
or in Appendix B, Hayes protocol reference.
If
you plan to use the PCM-7 in Tandy protocol mode only, you may skip
Chapter 3 and Appendix
B.
However,
if
you intend to use it in Hayes· pro-
tocol mode only, you may disregard Chapter 2, and Appendices A and D.
Refer also to the operation mariual which accompanies your
communica"'."
tions software package.
9
·
....
Tandy protocol mode operation 2
This chapter will give you an idea
of
what the DCM-7 can do in the Tandy
protocol mode. A Videotex Plus communications package for Tandy's Model
II, 12,
16
and 6000 microcomputers
is
used inthe sample sessions following.
With this software package you can communicate with a variety
of
informa-
tion services and host computer systems. The examples will help familiarize
you with some
of
the operations the Modem
is
capable
of
performing.
If
you are using an MS-DOS operating system, move directly to the auto
logon session using DeskMate's Telecom in Chapter 3, Hayes protocol mode
operation. XENIX users may want to skip to Appendix D.
For a detailed discussion
of
all the available commands in Tandy protocol,
refer to Appendix
A.
Manual v. automatic operation
When you want to dial an information service (such as CompuServe or Dow
Jones)
or
communicate with another person whose computer
is
also using
VIDTEX, set the Modem to manual operation mode.
In
this mode, you can
control what the system does by manually dialing and answering the phone.
- -
When you want the DCM-7
to
dial a phone number
or
answer the phone
for you, set it to automatic operation mode.
In
this mode, the Modem dials
the phone number you store in its memory
or
answers the phone when some-
one calls you. Automatic mode, for instance, lets you dial the information
service number without picking up the phone -just type the number along
with the proper DCM-7 programming commands on the computer keyboard.
Originate v. answer mode
To place a call to
an
information service
or
another person using VIDTEX,
set
the DCM-7 to originate mode. In this mode, the call originates from your
computer. When you want to receive a call (answer the phone), set the DCM-7
to answer mode. Note that originate and answer modes can be used either
manually or automatically.
Sample programming sessions
All Modem functions are controlled by ASCII encoded commands that you
send
from
your computer keyboard. Use the wake-up
command*
to open
the DCM-7 for programming.
1. Check again that all peripherals are correctly connected and receiving
power.
11
Tandy protocol mode operation
2. Set the
DIP
switches as follows:
3.
Flip the Modem's power switch
on
the front panel to the
ON
position.
4. Load.and run the Videotex Plus communications program. Refer to your
Videotex user's guide as well.
5.
At
TRSDOS Ready, type VIDTEX
(ENTER)
•
TERMINAL
READY
in-
dicator lights.
6. Set the communications protocol.
Be
sure the operation speed
is.
set to
300 Bps.
7~
Open
the
Modem for .programming by pressing * for the wake-up
command.
The Modem.
is
now in the command receptive state and
is
waiting for
you
to
begin programming or setting the internal switches that will tell
it what operations are
to
be performed.
8. When the * echoes
on
your computer screen, enter LIST command L
to display
or
list the Modem's current parameters. When the Modem
is
turned on, .the list shows:
MODE
TYPE
FCD
SPKR
ANSW
DTRY
TEST
NUMB
RATE
EXIT
=A
=0
= y
=Y
2
1
N
= s
=
OF
Automatic
Originate
Forced Carrier Detect
ON
Monitor speaker
ON
2 rings before Auto Answer
1 automatic dial try
Test
modeOFF
Telephone number stored in memory
Slow Dialing rate
Exit communication upon receiving <CTRL>
<0 > (ASCII
OF)
Note: The default parameter
of
line F
CD=
varies with the
po'-
sition
of
DIP
switches 2 and 6.
After the parameters are listed, the Modem returns to the command
recep..;.
tive state where
it
waits for further instructions. "
12
Chapter 2
CompuServe logon
CompuServe Information Service
is
widely known for its numerous on-line
services for both business and home computer owners. Dedicated telephone
numbers in major cities provide you access to CompuServe. Use your infor-
mation service user's guide to find out how to contact and use the service.
Since the DCM-7
is
already in the command receptive state -waiting for
your command -all you have to do to begin the logon
is
prepare the Modem
to dial the information service access number.
1. Press
@to
place the Modem in the dialer programming mode.
For
example,
if
you enter (111)555-1234 as your local access number for
touch-tone dialing, the sequence appears as:
DT(111)555-1234
If
you're using a rotary (pulse) type telephone, type R instead
of
T.
2. Whenthe phone number
is
properly formatted (see D command, Tandy
prQtocol reference),
press®
to force the Modem to seize
the
telephone
lin~s
and to begin dialing the number. OFF
HOOK
indicator lights.
- -
The
screen shows:
DIALING ... T(111)555-1234
CONNECT
Dialing
...
and connect are the Result codes (discussed later in this sec-
tion) which keep you informed
of
the status
or
progress
of
a phone call.
If
you received a? instead
of
the message shown, you probably entered
a key that the Modem did not recognize.
3. Press (CTRL) © and type the User ID number that you received with
the
software package when the screen prompts:
User ID:
4.
Next, type the password that you received with the software package
when.
the display prompts: -
Password:
Your password
is
not printed
on
the screen to retain its secrecy.
At this point, your logon to CompuServe
is
complete and you may begin
using the
s~rvice.
To use other information services and host systems, sim-
ply substitute the appropriate dialog as provided in the information
s~rvice
_user's guide.
13
Tandy protocol mode operation
Manual mode operations
When operating in manual mode, you control the system by manually dial-
ing and answering the telephone. Manual mode (answer or originate)
is
useful
when you want to talk by telephone to a friend at a remote location, and
later exchange computer data without redialing.
Example 1. Manual answer mode
The phone rings
and
you answer by picking up the receiver. After talking
a while to your friend, you decide to exchange information by computer
(telecommunications) without breaking voice call:
1. Your friend selects to be the originating station, while you are the an-
swering station. Set up your Modem by entering:
Wake up!
M Select manual mode.
A Select answer mode.
2. Give your friend time to set up the originating modem.
3. Press
®.
The Modem transmits carrier tone. The carrier
is
the sound
you hear through the built-in speaker
or
when you pick up the receiver
while the Modem
is
in communication with another modem.
4. The answer station always issues the X command first. After hearing
the answer modem's carrier tone, the originate station sends the X com-
mand to complete the connection. The Modem goes on line, and you'll
see the CONNECT result code
on
the screen.
5. Hang up
both
handsets.
Be
sure to keep 'quiet when the handset
is
OFF HOOK. Noise picked up could
cause errors in the
data
being passed by the modems.
Be
careful when you hang up the telephone since slamming
or
dropping the
phone back
on
the hook while the modems are controlling the lines could
disrupt carrier long enough to start a loss;..of-carrier disconnect sequence.
To return to voice communications after transmitting data:
1. Carefully pick up the handset (both modem stations).
2. Type
at
the keyboard that you will be aborting carrier. For example,
you might signal your friend by typing:
THAT'S ALL! I
AM
ABORTING CARRIER.
14
Table of contents
Other Tandy Modem manuals
