Tandy DCM-7 Operation Manual

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OPERATION

Cat. No. 26-1394

MANUAL

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TERMS

SOFTWARE

STORES

CUSTOMER

A.

B.

11.

LIMITED

A.

B.

C.
D.

E.

Ill.

LIMITATION

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C.

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IV.

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subject
A.
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F.

G.

V.

APPLICABILITY

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VI.

STATE

The
have

OBLIGATIONS

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copies

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capacity,
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the

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purchase
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within·

thirty
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~~~~~~ti~;

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to

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and

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additional
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limited

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copy

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applicable
All

copyright

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terms

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limitations

owner

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RIGHTS

warranties

other

rights

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CONDITIONS

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USE

INCURRED

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shall

arising

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two

(2)

·years

sales

document

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following

provisions:

otherwise

provided

medium

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use

use

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copies

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and

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manufacture,

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OF

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COMPUTER

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provided

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(4)

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backup

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furnishing

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apply

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purchased

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original

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subjected
the

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to

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original

replacement

of

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retail

store,

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CAUSED

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LEASED,

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FROM

SHACK

BE

OUT

OF

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SALE,

FOR
FOR

and/or

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computer.

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labeled

node

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computer

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extent

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to

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8/85

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to

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if

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a

This

The

equipment

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is in

strict

radio and television reception.

It has been

accordance

in
to

provide reasonable

However,

determined
terference by one

If

this

there

equipment

by

FCC

generates and uses radio

accordance

type

with

is no guarantee

turning

with

tested and found

the

specifications

protection

does cause interference

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equipment

or

more

of

Wants

the

manufacturer's

to

against such

that

interference

off

the

following

frequency

You

instructions,

comply

with

in Subpart J

and on, the user is encouraged

of

interference

will

to

radio or television reception,

measures:

energy.

the

limits

Part 15

not

to

If

not

for

of

FCC Rules,

occur

Know

installed and used properly,

it

may cause interference

a Class B

in

in

computing

which

a residential

.a

particular'

to

try

are designed

installation.

installation.

which

can be

to

correct the in-

device

to

• Reorient

• Relocate the

• Move

• Plug
branch

the

receiving antenna

the

computer

the

computer

circuits.

computer

with

away from the receiver

into a different

respect

to

outlet

the

so

Warning

This

equipment
pursuant
devices,
this

computer.

radio and TV reception.

Reproduction
tion,

of
been taken in the preparation
Corporation assumes no liability resulting
manual,

has been

to

Subpart J of

terminals,

Operation

certified

Part

printers, etc.)

with

to

comply

15

of

FCC Rules. Only peripherals

certified

non-certified peripherals is

300-Bps Intelligent Modem

© 1986 Tandy Corporation,

All Rights Reserved.

or

use, without express written permission from Tandy Corpora-

any portion

or

from

of

the use

this manual

of

of

the information contained herein.

with

to

comply

DCM-7

Fort

is

prohibited. While reasonable efforts have

this manual

receiver

that

computer

the

limits

with

and receiver are on

for

a Class B

the Class B

likely

limits

to

Operation Manual: .

Worth,

from

Texas 76102 U.S.A.

to

assure its accuracy, Tandy

any errors

different

computing

(computer

may be attached

result in interference

or

omissions in this

device,

input/ouput

to
to

2/86

Hayes ® is a registered trademark

XENIX®

is a registered trademark

10

9 8 7 6 5 4 3 2 1

of

Hayes Microcomputer Products, Inc.

of

Microsoft Corporation.

Contents

Introduction
1 · Description

Protocol (DIP) switches . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Communications protocol . . . . . .

...

...

..

....

of

the DCM-7

..

. ......... ........... ......

....

.. .. .. .. ..

• . . . . . . . • . • . . . . .

..

.........

....

.....

...

.. ..

.....

.....

..

... . .. .. ..

.....................•.......

2 Tandy protocol mode operation ...........................

Manual v. automatic operation
Originate v. answer mode
Sample programming sessions

Manual mode ·operations . . . . . . • . . . . . • . . . . . . . . . . . .

Automatic mode operations . . • . . . . . . . . • . . . . . . . . . . . . . . . .

Analog self-test mode

Always auto-answer mode operation . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . • .

On-line abort conditions . . • . • . • . . . . • . • . . . . . . . . . . . . . . . • . . . . . . . . . . • . . . . . . . . . . .

Result codes . . . • • . . • . . . . • • . • . . . . . . . . . . . • . . . . . . . . • . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . .

••....•...................•.•............•.•...........

...................•................•......

...............................•......•.....•.....

..................................•..•.......

...

. . . . . • . . . . . . . . . . . . • . . . . .

•.•

. . . . . . . . . . . . . . . . •

3 Hayes® protocol mode operation .........................

Command codes . . . . . . . . . . . • .

Registers . . . • . . . . . . . . . . . . . • . . . . . . . . . . . • . . . . . . . . . . • • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Result codes . . . . . • . • . . . . . . . . . . . . . • . . . . . . • . • . • . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . .

Logons in MS-DOS operating systems

.•

. . . . . . . . . . . . . .. . . . . . • . . . . . . . . . . . . . . . . • . . . . . . . . .

.......•..............•...........

Appendices

·1

. 3

8

11

11
11
11
14
15
17
18
18
19

21
21

24
26
26

A Tandy protocol reference .......................................

B Hayes protocol reference ........................................

Programming commands .

Registers . . . . . . . . . . . • . . . . • . • . . . . . . . . • . . • . . . . . . . . . • . . . . . . . . . . . . . • . • . . . . . . . . . . . . . . . .

Data

line monitoring

...

. . . . . . . • . . . . • . . . . . • . . . . . . . . . . . . . . . • . • . . . . . • . . . . .

.•....

~..................................................

C Connecting the DCM-7 ...........................................

Telephone connections . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • .

Computer connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Power source . • . . . • . . • • • . . • . • . • • • . • . • • . . . . . . . . . . . . . • • . . . • . . . . . . . . . . • . . . . • • . . . . .

31

39
39

44

48

49

49
51
51

Contents

D XENIX® operations ................................................. 53

E Troubleshooting ......................................................... 55

Analog loop self-test

Multi-line phone operation

F Specifications ..................................

Performance . . . . .

Physical/ environmental

•••••.....•....•••..•.....•.•..•.......••....••.•.......• 55

• • . . . . . . . . . • . • • . . . . . . • . . . • . . . . • . . . . . . . . . . . • . • . . . . 56

~

........................... 57

• . • . • . . . . • . . . . . . . . . • . . . . . • . • . . . . . . . . . . • • . . . . . . . • • . . . . . . . . . • . . . 57

• . . • . . • . . • • . . . . . . . . . . . . . . . • . . . • . . . . . . . . • . • . . • . . . . • . . . 57

G Schematic diagram ................................................... 59

Index

··············································································~··

61

Tables

1

DIP

Switch Settings in Tandy Protocol Mode . . . . . . . . . . . . . . • . . . . . . . . . 6

DIP

2
3 Result Codes (Tandy)
4 Commands with Parameters (Hayes)
5 Basic Command Codes (Hayes)

6 Dialing and Answering Command Codes (Hayes)

7 Registers (Hayes) .•......•.•.•... ..••• .. ... ....•.. .••..

8 Result Codes (Hayes)-

9 Programining Commands (Tandy)

10 List Settings and Related Commands (Tandy) . . . . . . . . . . . . . . • . . . . . . . . . 36

11
12
13

Switch Settings in Hayes Protocol Mode

• . . . . . • . • . • . • . . . . . . • . . .

...........................•........

.•......•............•.•.......•..........

.........•.•.••••...........•.•..•........•........•....

...........•..•.....................•..

Dialer Codes (Hayes)

Modem-to-Computer Cables . . . . . . . . . . . . . . • . • . . . . . . . . . . . . . • . . • . • . • . . . . . . . . .

Computer Option Boards . • . . . • . • . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . • . . . . . • .

.........................................................

....•...•...........•..•

•.

• . . . . . .

...

. . . • . . . • . . • . . . . . . . . . . . 19

.......

...................

..•.

.......•.

.•.

8

22
23
23
24
26
31

40
51
51

Introduction

With the Tandy direct-connect, 300-Bps Intelligent Modem DCM-7, your

or

computer or data terminal can communicate with other computers
nals using ordinary telephone lines.

The DCM-7 accepts data from a computer, converts the data into two­frequency tones and then sends the tones over telephone lines
modem. Conversely, the DCM-7 accepts tones from telephone lines and

data

changes those tones into
This direct-connect, Bell

automatic dial, answer
system configuration enhancements
provides operation in both Tandy and Hayes protocol modes - each selec-

at

table
In the Hayes protocol mode, your Modem

of
in Hayes protocol allow you
keyboard for the same operational modes used in Tandy protocol.

For example, you can set the DCM-7 for manual originate
mode,
incoming call when you are contacting a remote computer.
gram the DCM-7 for auto-originate or auto-answer mode and let the DCM-7
dial the telephone number
In either Tandy
perform operations such
specified number
communication

Another feature
you to monitor audibly the dialing and data communication progress. The
situation
codes.

Sample programming sessions are provided in each section
to help familiarize you with the various functions
you started using your Modem
familiar with
should keep you

the flip

running with Hayes software. Special command instructions and registers

in

is

of a DIP

which you manually dial the telephone number or answer an

is

of

reported visually

the manual and your Modem, the handy Quick Reference Card

and

or

Hayes protocol, the DCM-7 can be programmed to

of

rings and automatically redialing a phone number when

not established.

the DCM-7

"up-and-running!"

that your computer understands.

103-type modem

disconnect features, but also a wide range

switch.

to

program the DCM-7 from your computer

of

a remote computer or answer

as

automatically seizing the telephone line after a

is

a built-in monitor speaker which enables

on

your display with messages called results

as

quickly

is

not only designed with standard

as

well. Its microprocessing unit (MPU)

is

AT-compatible and capable

or

manual answer

Or

an

incoming call.

of

of

the DCM-7 and to get

as

possible. After you have become

termi-

to

another

of

you can pro-

this manual

,l

·

....

Description

of

the DCM-7 1

When power
panel will light - depending
DIP switch settings. These 6 indicators show the Modem's internal and
ternal operation status.

G)

POWER

@

POWER

when the Modem

®

OFF
to

@ TERMINAL READY indicator lights when the terminal

DTR

®

CARRIER
er

® TRANSMIT DATA indicator flashes when the Modem

data.

(j) RECEIVED DATA indicator flashes when the Modem

is

first applied, several

indicator lights when the power is ON.
switch turns the Modem

is

not being used.

HOOK indicator lights when the Modem

the

phone line).

(Data Terminal Ready) signal.

DETECT indicator lights when the Modem receives a carri-

tone

or

generates a "false" carrier. ·

CD

POWER I OFF HOOK I

®

on

the status

TERMINAL

READY

of

the indicators

of

ON

or

®

CARRIER

DETECT

on

the DCM-7's front

the computer's protocol and

OFF.

Be

sure.

to

turn

it OFF

is

ON

LINE (connected

is

supplying the

is

transmitting

is

receiving

dat~.

®

I TRANSMIT I RECEIVED

DATA DATA

TANDY'

300

BPS

INTELLIGENT MODEM DCM-7

ex-

Figure 1.

Front

3

Panel View

Description

CD

RS-232C standard DB-25
terface

@

PROTOCOL

@

PHONE

@

POWER

® WALL

of

the DCM-7

of

your computer.

(DIP) switches control the Modem's power-up condition.

jack

connects the telephone to the Modem.

jack

connects the Modem to the

JACK

phone line cord connects the Modem to the telephone line.

jack

connects the Modem to the RS-232C in-

AC

power adapter.

PHONE

CD

Figure 2

Before you connect the DCM-7, first read the instructions in Appendix
Connecting the DCM-7.
to

the computer! .

Be

Figure 3. A Typical Connection

..

Rear Panel View

sure to

turn

®

OFF

the power to the Modem

© ®

C,

and

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

munications software, you will want to
with Hayes communications software, set it to the Hayes protocol mode.
(Both

the

Tandy

with either communications software.)
Tandy protocol

When you select Tandy protocol mode, set
the Modem to set other
Figure 4 for the suggested switch settings in this mode (black portion shows
the switch position).

NO
NO

TRUE

1000

and 1200

DIP

and

switch functions as listed in Table

FUNCTION~

FUNCTION~

CARRIER!

DTR

TRUE

1 1

mode~

3000 personal computers can be used

m=;NO

~AUTO

If

you are using Tandy com-

set it for Tandy protocol.

DIP

Switch 7 to ON. This tells

1.

FUNCTION

ANSWER DISABLE

For

Refer to

I HAYES PROTOCOL

No

1

FUNCTION

1

use

l1~~~~~~11l~.

01

2 3 4 5 G 7 8

N -

FORCED DTR J I

FORCED CARRIER TANDY PROTOCOL

NO FUNCTION..
NO FUNCTION - . .

Figure 4.

DIP

1111

..

. . . ... AUTO ANSWER ENABLE

Switch Settings in Tandy Protocol Mode

5

1~

I L NO FUNCTION

..

NO

FUNCTION

Description

of

the DCM-7

Table 1.

SW

2

3

4

5

6

7 Should be ON Tandy. Sets the Modem to Tandy protocol mode.

8 Should be OFF No function.

Position

ON

OFF

ON

OFF

Should be OFF
Should be OFF
Should be OFF

ON

OFF Auto-answer disable. Modem assumes auto-originate

DIP

Switch Settings in Tandy Protocol Mode

Function

DTR

Forced

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

Forced/True carrier. Modem selects between forced

carrier detect and true carrier
the G command input.

No function.
No function.
No function.

Auto-answer enable. Modem assumes auto-answer

upon power-up.

upon power-up.

(Data Terminal Ready). Modem accepts

G command.

detecf2> according to

*

1)

Forced carrier detect ... Modem issues a forced carrier signal to the local com-

as soon

puter

*2) True carrier detect ... Modem will be off until it receives true carrier from the

remote

DIP

Switch 2 interlocks with

i

ON

i

ON

as

computer.

power is turned ON.

DIP

Switch 6 as follows:

Modem assumes auto-answer with forced carrier
detect.

Modem assumes auto-originate with forced
rier detect.

car-

6

Chapter I

i

ON

~

2

i

ON

~

2

Hayes protocol
When you want to use your DCM-7 in Hayes protocol mode, position

7 to

OFF.

from those in Tandy protocol. Refer

tings

in

SEND

NUMERIC

VERBAL RESULT CODES

NO

~

6

~

€)

In this protocol mode, the remaining switches function differently

Hayes protocol mode.

RESULT CODES
RESUL_ T COD-

TRUE

FORCED

FORCED

RESULT CODES ---_

Modem assumes auto-answer with true carrier
detect at power-on. The true/forced carrier con­dition can be changed with the G command.

Modem assumes auto-originate wlth forced car­rier detect at power-on. The true/forced carrier
condition can be changed with the G command.

to

Figure 5 for suggested switch

~COMMAND

ES

-

CARRIER~

TRUE

DTR

11~~-

~1

ornJ

CARRIER~

11

1 1

w~~w~~

2 3 4 5

I

11 · 111

- - . _ - AUTO ANSWER DISABLE

- - - COMMAND ECHO OFF

JG-

jHAYES

1

€)

7 8

--

AUTO.ANSWER ENABLE

rNo

FUNCTION

1~

LNo

FUNCTION

TANDY PROTOCOL

ECHO

PROTOCOL

Switch

set-.

ON

Figure 5.

DIP

Switch Settings in Hayes Protocol Mode

7

Description

of

the DCM-7

Table 2.

SW

2

3

4

5

6

7 Should

8 Should

For

Set Switch 4

•Position

ON

OFF True

ON

OFF

ON

OFF

ON

OFF

ON

OFF

ON

OFF

.easy operation, position Switch 5 to OFF

to

DIP

be

OFF

be

OFF

OFF

and Switch 3 to

Switch Settings

Forced

Forced carrier detect.
True carrier detect.

Displays verbal result codes.
Displays

Result codes disabled. Disables Switch

Result codes enabled. Enables Switch 3.
Command echo disable.

Command echo enable.
Auto-answer disable.

Auto-answer· enable.
Sets the Modem
No

OTA.

OTA.

Function.

in

Hayes Protocol Mode

Function

numeric result codes.

to Hayes protocol mode.

to

echo the command line.

ON

to

send the verbal result codes

3.

to

the screen.-

Communications protocol

The following criteria must be met before computer'-to-computer communi­cation can ·occur.

1.

Both

computers must have the same communications protocol:

300 bits/second (Bps)

Word length

Parity (even, odd
Number

See your computer owner's manual for instructions

munications protocol.

One modem must be in ORIGinate mode and the other must be in

2.
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.

of

stop bits

(7

bits

or

or

8 bits)
none)
(1

or

2 bits)

on

setting the com-

AN'"

8.

Chapter 1

The DCM-7 provides automatic and manual operations in both originate and

oi

answer modes. When opened for programming by the wake-up
code sequence, it will automatically synchronize the speed rate, word length,

and

parity
system.

Helpful Tip:

Whe,n

. garbled data, use the self-test mode to help you find the cause

Refer
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
tocol mode only, you may disregard Chapter 2, and Appendices A and D.
Refer also to the operation mariual which accompanies your
tions software package.

stop-bit numbers (communications protocol)

you use your

to

the section

DCM-:-

7 for the first time

on

self-test in Appendix A, Tandy protocol reference

B.

However,

or

if

you intend to use it in Hayes· pro-

when you seem to be getting

of

attention

your computer·

of

the problem.

communica"'."

9

·

....

Tandy protocol mode operation 2

This chapter will give you an idea
protocol mode. A Videotex Plus communications package for Tandy's Model

16

II, 12,
With this software package you can communicate with a variety
tion services and host computer systems. The examples will help familiarize
you with some

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
refer to Appendix

and 6000 microcomputers

of

the operations the Modem

of

A.

of

what the DCM-7 can do in the Tandy

is

used in the sample sessions following.

of

informa-

is

capable

all the available commands in Tandy protocol,

of

performing.

Manual v. automatic operation

When you want to dial an information service (such as CompuServe or Dow
Jones)
VIDTEX, set the Modem to manual operation mode.
control what the system does by manually dialing and answering the phone.

When you want the DCM-7
for you, set it to automatic operation mode.
the phone number you store in its memory
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.

or

communicate with another person whose computer

In

- -

to

dial a phone number

In

this mode, the Modem dials

or

answers the phone when some-

or

is

also using

this mode, you can

answer the phone

Originate v. answer mode

To place a call to
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.

an

information service

or

another person using VIDTEX,

Sample programming sessions

All Modem functions are controlled by ASCII encoded commands that you

from

send
the DCM-7 for programming.

1. Check again that all peripherals are correctly connected and receiving

your computer keyboard. Use the wake-up

power.

11

command*

to open

Tandy protocol mode operation

2. Set the

3.

Flip the Modem's power switch
Load.and run the Videotex Plus communications program. Refer to your

4.

DIP

switches as follows:

on

the front panel to the

ON

position.

Videotex user's guide as well.

5.

At

TRSDOS Ready, type VIDTEX

(ENTER)

•

TERMINAL

READY

dicator lights.

6. Set the communications protocol.

300 Bps.

7~

Open

the

Modem for .programming by pressing * for the wake-up

Be

sure the operation speed

command.
The Modem.

you

to

it what operations are

8. When the
to display
is

turned on, . the list shows:

MODE
TYPE
FCD
SPKR
ANSW
DTRY
TEST
NUMB
RATE
EXIT

Note: The default parameter

sition

is

now in the command receptive state and

is

waiting for

begin programming or setting the internal switches that will tell

to

be performed.

* echoes

or

=A

=0

= y

=Y

2
1

N

= s

=

OF

of

on

your computer screen, enter LIST command L

list the Modem's current parameters. When the Modem

Automatic
Originate
Forced Carrier Detect
Monitor speaker
2 rings before Auto Answer

automatic dial try

1
Test

modeOFF
Telephone number stored in memory
Slow Dialing rate
Exit communication upon receiving < CTRL >

< 0 > (ASCII

DIP

switches 2 and 6.

OF)

ON

of

ON

line F

CD=

varies with the

After the parameters are listed, the Modem returns to the command
tive state where

it

waits for further instructions. "

is.

set to

po'-

recep..;.

in-

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

your command - all you have to do to begin the logon

is

already in the command receptive state - waiting for

is

prepare the Modem

to dial the information service access number.

1.

Press

@to

place the Modem in the dialer programming mode.

example,

if

you enter [phone] 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

2. When the phone number

prQtocol reference),

lin~s

and to begin dialing the number. OFF

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

If

you received a? instead

is

properly formatted (see D command, Tandy

press®

to force the Modem to seize

HOOK

of

the status

of

the message shown, you probably entered

or

progress

the

indicator lights.

of

of

telephone

a phone call.

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

At this point, your logon to CompuServe
using the

s~rvice.

ply substitute the appropriate dialog as provided in the information

is

not printed

on

the screen to retain its secrecy.

is

complete and you may begin

To use other information services and host systems, sim-

s~rvice

_ user's guide.

For

T.

13

Tandy protocol mode operation

Manual mode operations

When operating in manual mode, you control the system by manually dial-

is

ing and answering the telephone. Manual mode (answer or originate)
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

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 an­swering station.

M

A Select answer mode.

2. Give your friend time to set up the originating modem.
Press

3.

4. The answer station always issues the X command first. After hearing

5. Hang up

Be

sure to keep 'quiet when the handset

cause errors in the
Be

careful when you hang up the telephone since slamming

phone back

disrupt carrier long enough to start a
To return to voice communications after transmitting data:

1. Carefully pick up the handset (both modem stations).

2. Type

®.

you hear through the built-in speaker
while the Modem

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

at

you might signal your friend by typing:

THAT'S ALL! I

and

you answer by picking up the receiver. After talking

Set up your Modem by entering:

Wake up!
Select manual mode.

The Modem transmits carrier tone. The carrier

or

when you pick up the receiver

is

in communication with another modem.

CONNECT result code

both

handsets.

data

being passed by the modems.

on

the hook while the modems are controlling the lines could

the keyboard that you will be aborting carrier. For example,

AM

ABORTING CARRIER.

on

the screen.

is

OFF HOOK. Noise picked up could

or

loss;..of-carrier disconnect sequence.

useful

is

the sound

dropping the

14

Chapter 2

3. After making sure your handsetis OFF HOOK, enter the abort charac­ter (

e"'fRL) @ to force the Modem

not

have the CTRL key, refer to your computer manual to find out the
of

hex value

key
redefinition

After 3 seconds
result code,
Modem

and

is

in OFF-LINE mode. Press ~ to return

OF,

or change the

@.

Refer to Appendix A, @ command. ·

of

inactivity, your Modem logs out with the DISCONNECT

your friend's modem (if automatic) shuts down, too. The

OFF

LINE.

abort

character using abort character

If

your computer does

to

the command recep-

tive mode.
Example

l.

2:

Manual originate mode

Set the Modem for manual originate mode.

@ for originate. Then, press (!) to check the current parameter settings.

Press~

for manual and

The first two parameters should show:

MODE=

TYPE = 0

M

2. Now pick up the telephone and dial the information service phone num­ber. When the information service answers the phone, you will hear a
high-pitched tone.

3.

Press

®.The
tects the carrier tone, it issues low-pitched tone. Then it goes
and

sends the CONNECT result code to the screen. ·

4.

Gently

hang~

OFF-HOOK indicator lights. As soon as the Modem de-

ON LINE

the phone. You can then begin following the instruc-

tions detailed in your Videotex and information service user's guides.

Automatic mode operations

The DCM-7 can be programmed to make a call
automatically.

In

automatic mode operation, you can call
service without picking up the phone - just type in the phone number
your computer keyboard. You can also tell the Modem to auto-answer your

telephone.

Example 3: Automatic answer mode

1.

To

set the Modem for automatic mode, first type * to enter command
mode, then type
shows

MODE=

firm that the mode

L to display the current parameter· settings.

M, then press ~ for automatic mode. Type L to con-

is

now A for automatic.

or

answer your telephone

an

information

If

on

screen

15

Tandy protocol mode operation

2. Type A to set the Modem

does not show

3. Press ®

the

value

to

force the Modem out
auto-answer mode. The Modem will then wait for the telephone
and

sends:

WAITING

FOR

RING

to

the answer mode

A.

of

command receptive state

if

the

TYPE

parameter·

and

into

to

ring

4. When the phone rings, the Modem begins counting the rings and sends
the RING result code to the display for each ring. After 2 rings, it answers
by seizing the telephone line and asserts carrier. The calling modem replies
with its carrier. Both modems are now

ON

LINE

and

telecommunica-

tions can begin.

is

set

to 2 at

The ring number

power-on. This means your Modem will seize

the phone line after 2 rings. When you want to change this number, press

OJ

for the ring change command when the Modem is in command recep-

tive mode. The display prompts:

ANSWER

When you do
by pressing (ENTER) , which is the CR (Carriage Return) key.
the ring number, type
the ENTER key is accepted.
"echo" the typed key (if displayable)

If

the key you press is a valid entry, the Modem sends the next prompt:

RETRY

For

the time being, press (ENTER)

If

either modem breaks
the abort character,
then the
answer mode
mode,
You can
detects the

ON

1-9

not

FOR

1-9

WAITING

and

it

will continue

turn

OFF

*, it will change

RINGS OR

need

to

in

TIMES OR CR

the

the

FOR

monitors

to

CR

FOR

NO

CHANGE =

change the number

the new number. Note

If

you press any other key, the DCM-7 will

and

FOR

to

connection after a successful

of

rings, answer this

that

only a number key

ask the question again.

NO CHANGE =

skip.

data

prompt

To

change

exchange with

DCM-7 will send the DISCONNECT result code,

RING

result code. This means it returns to auto-

the

line. As long as the Modem

monitor the telephone line for

is

in auto-answer

an

incoming call.

this call-waiting mode by pressing eJ. When the Modem

to

auto-originate mode and return

to

the command

or

receptive state.

Example 4: Automatic originate mode

in

Step 1

of

1. Follow the procedure

2. Type

0 to set the Modem

not show the value

to

0.

Example 3, Automatic answer mode.

originate mode

16

if

the

TYPE

parameter does

Chapter 2

3. Enter the telephone number you want to dial using the D command
Appendix A, Dialer programming mode). You can also specify the dial­ing method (either pulse
which may be necessary
ple, in the phone number below:

DT9P1234567

T indicates tone, 9
pause and the digits
on

storing a telephone number, refer to Appendix A.

Press

00

4.
gin dialing the number.

5. After detecting the carrier tone
line

If

the Modem does not detect the carrier tone

30

seconds after dialing (due to busy

off

line after sending the NO CARRIER and DISCONNECT result code. To

dial the number again, press
number stored in dialers memory.
number, the Modem displays the

You can also program the Modem to automatically redial (RETRY) the num­ber

in

advance.

respond to the first prompt, a second prompt appears:

RETRY FOR 1-9 TIMES OR CR FOR NO CHANGE =

Again, a valid entry
tries.

If

to force the Modem out

is

connected, the Modem

Il1

this case, press

is

no change is required, just press ( ENTER) •

or

touch".tone), the dialing speed and any pause

to

access

an

outside line in a PBX. For exam-

is

the access code

1234567 are to be dialed.

~·

a number or ( ENTER ) • Input the desired number

to

the outside line, P

For

of

command receptive state and to be-

of

the answer modem, after the telephone

is

ON

LINE.

of

the answer modemwithin

or

no answer condition, etc.), it goes

00

. The Modem automatically dials the

If

you press ® without having stored a

NO NUMBER result code.

CD

for the dial retry command. After you

is

the 2-second

more information

(See

of

-·---------·-----------n

Analog self-test mode

Type

Q,

then type L to confirm
changed to
CONNECT and you are in the self-test mode. Type any characters
keyboard.
RECEIVED DAT A indicators blink simultaneously and the characters you
typed will appear
Check all cables and connections and run the test again. To abort self-test

mode, press

Y.

Type X to

If

the DCM-7 is working properly, the TRANSMIT DATA and

on

the display.

. ( CTRL ) @ for the abort character.

that

the value

execute the test command. The Modem displays

If

not, there are problems with the circuit.

of

the TEST parameter

is
on

now

the

Tandy protocol mode operation

Always auto-answer mode operation

The Modem assumes always automatic answer mode operation when the DIP
Switch
When you type
to
connecting,
returns

This setting is useful when you use the Modem mainly in the answer mode.

6

is

set to

on

at power up, and begins monitoring the telephone line.

* , the Modem enters command receptive mode and changes

automatic originate mode as

or

after receiving the C (clear memory) command, the Modem

to

automatic answer mode.

i:ri

normal automatic answer mode. After dis-

On-line abort conditions

After establishing communications with a remote modem, the DCM-7
monitor mode. In this mode, the parameters are constantly scanned.
one

of

these parameters fails, the DCM- 7 will break communications and

go

OFF

LINE immediately. The parameters monitored include loss

er, the
Loss

The carrier monitored
false carrier generated by the DCM-7. In all modes, except
is removed for longer
and drop the phone line.
loss

In

completed (a
DCM-7
to
keys, press

Manual abort entry

When you send a CTRL 0
with the
will exit monitor mode.

DTR (Data Terminal Ready)
the DCM-7 will terminate communications, just as

abort

character

of

carrier

of

carrier is ignored.

automatic originate mode, when the Modem is waiting for a call

30'-second delay time between dialing

is

looking for a valid carrier signal), you can command the DCM-7

abort the call by inputting any keys including

~to

@ key and do not send any other character for 2 seconds, the DCM-7

and

space disconnect.

is

the one

than

0.3 seconds, the Modem will exit monitor mode

If

the carrier interruption

set the Modem

(OF

HEX)

is

also scanned in this mode.

that

is

sent over the telephone line, not the

TEST,

is

less

than

and

disconnect where the

*.

If

you aborted with other

to

command receptive mode.

or

another character you programmed

If

the DTR

if

the carrier had failed.

of

if

0.3 seconds,

is

is

in

If

any

carri-

carrier

to

be

OFF,

18

Chapter 2

Space disconnect
Your DCM-7 will drop the phone line any time it receives a continuous

RS-232C SPACE (ASCII BREAK or null with no start and stop bits) for
3 seconds from the

is

This

called space disconnect and

r~mote

modem or for 1.5 seconds from your computer.

is

in accordance with Bell

1031

standards

for short and long space disconnect.
To regain control over the Modem after disconnection, input wake-up code

*.

The Modem returns to the command receptive state with the same
parameter settings as before. When you want to change the parameters to
the default settings, press

© .

Note: The clear memory command C sets the Modem to off-line

~

mode. Press

again to enter command receptive mode.

Result codes

The DCM-7 sends the result codes to report its status or telephone line con­dition.

Table 3. Result Codes

Result Code

?

NO

NUMBER

DIALING ...

CONNECT

NO CARRIER

. DISCONNECT

WAITING

RING

FORCED
IS

ON

FOR

CD

RING

SWITCH

The command input is invalid.

Th~re's

Modem
Detected
Does not

Goes

Mod~m

ring

D~tects

phone line. ·
Since

accept G command (Refer to

Protocol (DIP) switch.)

no number to be

is

dialing the number that follows.

carri~r

receiv~

on

hook after the connection .

is

monitoring the

signa,I.

an

incoming ring

DIP

Switch 2

Meaning

dia,l~d

and goes

carrier or lost it.

on

tel~phone

~

s~gna,I

i~

ON, Modem

lin~.

Chapt~r

in

the memory.

line for a

on

the tele-

do~s

1

not

19

Hayes protocol mode operation 3

In Hayes protocol mode, commands instruct the DCM-7's operation and
register values determine how the commands will be executed. The command

is

structure
mand, which makes the DCM-7 Hayes-software compatible.

Command codes

All command lines in Hayes protocol mode begin with the
code) string and end with a carriage return (
in uppercase letters,
upper- or lowercase letters.
will automatically set the operation speed (in Bps)

You can store a sequence
provided the command line does not exceed the 40-character buffer capaci­ty.

These commands, however, must be entered in logical order in order to

be

executed.

will not

Example 1. Sample command line

AT

Now, to review the commands, one by one:

AT

V1

S6=3
DP9,

T

R

(ENTER ) End of command line. Execute all commands.

The attention code AT, control characters and spaces do not take up space
in the command

make it easier to read does take up space. Input the attention code AT, reset
command Z, or
mand buffer.

patterned from the industry standard AT-string-interface com-

ENTER

) •

AT

must be entered

but

the commands following can be entered in either

When the

of

commands in the command buffer memory,

If

the command line

execute

V1

the commands and instead sends an error result code (Table

S6

= 3 DP9, T(111)123-4567R (ENTER)

B~ginning

receptive mode.
Displa,y

in

this chapter.)
Wait 3 seconds for the dial tone.
Dial 9 by

of

regist~r

Touch-tone
Cha,nge

buff

turn

of command line.

the verbal result code. (Refer to Result codes later

pul~e

SS).

dia,I

to

answ~r

er. The punctuation used in the telephone number to

OFF the power supply

AT

command

exceeds

dia,ling, then pause 2 seconds (defa,ult

(Refer to

the

the buffer-character limit, the Modem

Plac~

th~

section

t~lephone

mode

a,nd

wait for carder.

of

is

received, the DCM-7

and

parity.

the Modem

on

Registers.)

number that

follow~.

the Modem to clear the com-

AT

(attention

in

command

8).

valu~

21

Hayes protocol mode operation

The basic commands needed for programming the Modem in Hayes pro-

5.

tocol mode are provided in Table
commands. For a detailed explanation
B,

Hayes protocol reference.

Table 6 lists the dialing and answering

of

each command, ref er to Appendix

Commands with parameters
Some

of

the commands have parameters. The parameter value, usually 0,

1 or 2, follows the command. When the command parameter

of

the Modem assumes a value
not echo when parameter
issued. E used alone

Code Parameter

Q

v

0 Result codes ON. Defined by DIP Switch

1

0 Numeric result codes. Defined by DIP Switch

1

is

the same as

Table 4. Commands with Parameters

Result codes

Verbal result codes.

0. For example, the echo command E does

0

is

assumed.

It

does echo when parameter 1

EO.

Function

OFF.

is

Default

not used,

4.

3.

E 0 Commands are not

echoed.

1

F 0 Half duplex.

1

M 0 Monitor speaker always

2

Echo commands.

Full duplex.

OFF.

Monitor speaker
until carrier-detect.
Monitor speaker always
ON.

ON

c 0 Transmitter OFF.

1 Transmitter ON.

H 0

ON

HOOK (phone line

disconnected when not

use).

OFF-HOOK (phone line
connected regardless of
its condition).

is

in
is

Defined by

F1

M1

C1

HO

DIP Switch

5.

is

'JO

22

Table 5. Basic Command Codes

Code Description

AT Attention Code

CR Carriage Return

BS

+ + + Escape

0 On-line

z

Backspace

Codf3

Reset

Table 6. Dialing and Answering Command Codes

Chapter 3

Function

Wakes up the Modem to command receptive
st?te. Starts the command line.

Closes
mands. Register
return character.

Edits the command line by deleting charac­ters one
backspace character.

Returns the Modem to command mode from
on-line mode. ·Register
code character.
guard time.

Returns the Modem to
conim?nd mode.

Resets the Modem to default condition.

the .command line ?nd executes com-

S3

defines the carriage

·

by

one. Register

s·12

S5

defines the

S2

defines the escape

defines the escape code

on-line mode from

Code Description

Sets the Modem to originate ? telephonf3 call.

D command par?meters include: 0-9, (

space, *, and # .

P Pulse
T Touch-tone
R Reverse

(comm?) Follows

; (semicolon)

A/

A

Pause

Rf3peat

Answf3r

Dia.I

Dial Sets the Modem to touch-tone dialing

Modf3

Comm?nd Repeat$ the comm?nd line. AT and ENTER

Mode lmmedi?tely

Sets the

Automatically changes the Modem to answer
mode

C?uSe$
set by Register

Returns the
dialin9.

are not

without

Function

Modf3m

?fter ? call

the Modem to pause while di?ling.
the

nf3cess?ry

waitin9 for a ringin9 sign?I.

23

to pulse dialing mode.

i$.

originated.

?Ccess

code. Length of pause

SB.

Modf3m

Sf3ts

to comm?nd mode ?fter

for this command.

the Modem to

·

answf3r

),

modf3.

is

mode

Hayes protocol mode operation

Registers

Registers are used to store the parameters which control communications.
Each register has variables
plies information

on

registers:

Register Range Unit Function Default

so

S1
S2
S3
S4
S5
S6
S7 1-255
SB

S9

S10 1-255

S11
S12 20-255
S13-S15
S16

0-255 Ring Defines the rings in answer mode.
0-255 Ring Counts the rings.
0-127 ASCII code Defines the escape code character. 43
0-127
0-127 ASCII code Defines the LF code character.
0-32,127
2-255 Seconds Defines the dial tone wait time. 2

0-255

1-255

50-255 Millisec. Defines touch-tone dialing speed. 70

0

that

determine how the DCM-7 operates or sup-

the Modem's current condition. The DCM-7 has

Table 7. Registers

ASCII code

ASCII code Defines the BS code character. 8

Seconds
Seconds Defines pause

1110

sec. Defines carrier detect response 6

1110

sec. Defines carrier loss time to hang 7

1150

sec. Defines escape code guard time.

Defines the

Defines the carrier wait time.

(actual maximum value is 54, but
a value up to 225 can be input).

time.

up.

Not used.
Self-test mode OFF.

Self-test mode ON.

CR

code character.

duration for comma

14

0*3)
0

13

10

30
2

so

0

*3) When DIP SW 6 is OFF, the Modem will power-up in auto answer with

Register
register

ters; registers

SO

defines the number

Sl

counts the rings; registers

of

ringing signals before a call

S2-S5

define the function key charac-

S5-S12 control the function time and register S16

is

answered;

is

self-test.

Note: The ASCII code values are expressed in decimal.

24

so=

1.

for the

Chapter 3

Command
You can read the current value

the registers

mand

Sx? Check the register value

To

check the value

are displayed

value

AT S2? (ENTER)

On

the screen, you will see -

043

OK

You can also check the values
To

check the values

AT S3? S4? (ENTER)

syntax

to

your particular environment by using the Sx?

syntax.

of

on

the screen

of

register 82, type:

of

a register

or

assign a new value

a register, use the Sx? syntax. The value

in

of

register 83

qecimal numbers.

of

plural registers in the same command line.

and

register 84, type:

For

example,

to

or

Sx=

n com-

of

the registers

to

check the

match

The screen might show:

013
010

OK

Sx=n

Use the
the value 3

AT

Change the register value

Sx=

SO=

n syntax

to

3 ( l;N"fER)

register

to

SO,

assign

or

change the value

type: ·

of

a register.

To

assign

After changing the value, the Modem signals OK. Another syntax for chang-

regis~er

ing a

AT

SO

AT?
AT=

3 (

For

more information

value is:

(ENTER)

(ENTER)

EN"fER

Set the pointer to register

Read the value of

)

Assign

on

the registers, refer

th~

new value 3 to

SO.

to

SO.

SO.

·

Appendix B, Hayl'S protocol

reference.

25

Hayes protocol mode operation

Result codes

Result codes are displayed in either numeric
mand line

Command

Ql

is
you can see the codes
or

verbal (Vl) codes.

The default values
when
unless

Numeric

is

executed.

Q determines whether the result codes will be displayed. When

selected, the result codes will not be displayed. When

on

the screen. Command V selects either numeric

of

these controls are fixed by

DIP

Switch 4

QO

is

entered from the keyboard. (Refer to Chapter

0 OK Executed the command line without errors.

CONNECT

2

RING Detected
NO CARRIER Carrier was lost

3

4

ERROR Error

is

set to ON, the result codes do

Table 8. Result Codes

Verbal Meaning

Detected carrier.

an

in

the command line, command
(not recognized by the Modem), or the command
line exceeds command buffer size.

or

verbal code after the

QO

is

selected,

DIP

switches.

not

incoming phone line ring signal.

or never heard.

appear

1,

DIP

For

example,

on

the screen
switches).

is

invalid

com"'

(VO)

Logons in MS-DOS operating systems

With DeskMate's Telecom applications program and your Tandy Personal
Computer, you can easily program your DCM-7 to log
information service

-Follow the instructions in your DeskMate Tutorial
for setting the parameters and using the functions available. Depending
the computer you are using, the procedures may differ slightly from those
shown. A Tandy

1. Power up the computer and load your communications software. Set

the

DIP

switches

or

another terminal either manually

1000

PC

is

used for the examples following.

on

the DCM-7 as follows:

on

to a host computer,

or

automatically.

and

Reference manual

on

I

~~.

~~.~~~~I

1 2 3 4 5 6 7 8

26

g~

·chapter 3

2.

At

the Main Menu, select Telecom and change the TELECOM-STATUS

screen io show:

Autodi?I

BAUD
Data Word Length

P?rity .

Number of Stop Bits
XON/XOFF Flow Control
ASCII

Line Feed Filter

Echo (Half Duplex)

R~dial

Mod~m

Rate

Character Filter

( # of Retries)

Yes

300

8 BITS
NONE

1 BIT

ON

OFF
OFF
OFF

0

3. Select "Yes" for the Autodial Modem status setting and press
When the DEFINE MODEM FOR COMPUTER DIALING screen ap­pears, change the dialing sequence to show:

PAUSE: 2 Pause for 2
SEND: ATDT W?ke

touch-tone

NUMBER Send

terminal mode.

SEND: "M

WAITC Wait for carrier

Note:

If

your telephone system requires pulse, rather than touch- .

S~nd

cute the commands:
tinuing.

tone dialing, change ATDT to

4.

Press

(f=12)

twice to return to the TELECOM-STATUS screen after sav-

ATDP

second~.

up

and originate ? call using

di~ling.

number which will

~M

to force the DCM-7 to exe-

d~tect

b~

before con-

in the first SEND line.

input

ing the dialing sequence.

@.

·

at

Manual logon

1. Enter terminal mode from the

2.

At

the TERMINAL MODE screen, press

number

of

the information service, then press (ENTER ) •

TELECOM-STATUS

@ID

and type in the telephone

scre~n

3. After the connection has been made successfully, proceed with
procedures step by step.

27

(

(EID

).

thelogon

Hayes protocol mode operation

Automatic logon •

1.

At

the TELECOM-STATUS screen, press
and enter your log file name, then press (
the

STATUS line. After selecting the parameters, press (F12) to return

to

the original screen

and

complete the rest

(§)to

ENTER ) • Press

create

of

file. When completed,

an

autolog file

(ED

the screen for your autolog file might show:

STATUS:Y,30,8,
CALL: 123-4567 (Use your local TELENET number.)

PAUSE:S
SEND:
RECV: TERMINAL=

SEND: D1"M

RECV: @

SEND: C 60942"M

RECV:

SEND: DJNS"M

AM''M

????

2. Press ( F12) (ENTER )

N,

1,0N,OFF,OFF,OFF,O

to

save this autolog file

and

return

TELECOM-STATUS screen.

3. Input

@ filename (ENTER ) to execute your autolog file. When the

logon sequence is entered correctly, the DCM-7 will dial your local ac­cess number' connect to the service, then automatically execute the rest

·or

the autolog file.

to create

to

the

28

Appendices

I

·

....

Tandy

protocol ref ere nee A

When you use your DCM-7 in automatic mode, you

or

numbers

pick up your telephone receiver

does all that for you. As long as you're going

to

to

don't

have

answer a call

be

at

your computer through-

-your

to

dial any

DCM-7

out communications, you can control the DCM-7 and your telephone through
your computer keyboard.

You can also send
at

your computer keyboard.

gram

and

use the commands
(automatic originate)
By programming your DCM-7
computer after

take advantage
The DCM-7

9. These commands can be entered either

Command

@

A,

a

C, c

D, d

P, p

R,

r

T,

t

E, e

F,

f

G, g

I,

i

L,

I

M,m

0,

0

P, p

Q,

q

S, s
X,

x

or

receive

12

midnight, for example, you'll save time

of

lower telephone rates.

is

completely programmable using the commands shown in Table

Table 9. Programming Commands

Wake up command
Redefine abort character
Answer mode operation
Clear memory
Enter dialer programming mode
Pause subcommand
Pulse (Rotary) dial subcommand
Touch-tone dial subcommand
Command echo disable/enable toggle
Fast dialing speed
Forced carrier detect toggle
Ring/Retry change command
List parameter settings
Manual/automatic toggle

Originate mode operation

Monitor speaker ON/OFF toggle
Self-test command
Slow dialing speed
Execute command(s)

data

from another computer while

Just

write a BASIC

to

program your DCM-7

or

answer (automatic answer) the phone unattended.

to

download daily information

Description

1.n

or

machine-language pro- .

upper-

or

lowercase letters.

CTRL 0 (HEX
Originate mode

Pulse (Rotary)
Echo
Slow dialing
DIP Switch 2/6
Ring 2/no

Automatic
Speaker ON

you

to

dial a number

to

another

and

be

Default

enable

retry

are not

able to

OF)

31

Tandy protocol reference

Command description

This section details how to program the DCM-7 using the commands listed
in Table 9.

·

* Wake-up command

This command
off-line state and into the command receptive state.
will need to precede any command with the

The wake-up command
(2)

abort the waiting-for-carrier state (after dialing

terrupt the waiting-for-ring state when the DCM-7
When the

to ring), it terminates the answer mode.
When used while the DCM-7

Modem will stop dialing, displays
mand receptive mode.

The

* command can be used

be echoed to the computer,

is

used

to

wake up the DCM-7 -

is

also used to (1) abort (turn off) the dialing process;

*

is

used while the DCM-7

that

is, switch from the

At

initial power-up, you ,

*

..

is

complete); and

is

in auto-answer mode.

is

waiting for a

is

dialing in automatic originate mode, the

DISCONNECT and return

at

any time while in command mode.

but

no action will occur.

tdephone

call (phone

to

(3)

in-

the com-

It

will

@ Redefine

The abort character allows the Modem to be disconnected under software
control. With this command, you can change the. default abort character
CTRL

To program this symbol, press
be stored
CTRL

CTRL R would be listed as EXIT
character, it
the echo switch

The DCM-7 will watch for transmitter activity for 3 seconds after the abort
code
will abort any
within

0 into any ASCII character you like.

as

the abort character. For example, to change the abort code from

0 to CTRL R after doing a List command, you would type:

@ CTRL R

will

not be echoed on the screen. Only @

is

is

sent.

If

there

ON-LINE activity in progress.

that

3-second period, the DCM-7 will ignore the abort command.

abort

character

@ . The next key the Modem receives will

==

12

(in HEX). When you enter the ASCII

will

be echoed, provided

not disabled.

is

no activity during that 3:-second period, the computer ,

If

there

is

keyboard activity

32

Appendix A

A, a Answer mode operation
The Modem

up. The A command
em to an answer modem.
a call from a modem which

is

defaulted to operate in originate mode when first powered

is

used

to

change the DCM"7 from

Use the answer mode when you want

is

operating in originate mode. The M command

an

originate mod-

to

receive

(manual/automatic toggle) determines whether the Modem will wait for the
telephone to ring (auto answer) or seize the telephone line as soon as you

exit the command receptive state with the X (manual answer).

You can enter this command repeatedly. There

is

the DCM-7
plications software

already in answer mode. You rriay want to

to

be sure the DCM-7

is

no harm in entering A when

put

A in your ap-

is

in answer mode before running

the program.
C, c Clear memory

The C command clears the DCM-7's memory and resets all the parameters
to the default values. There
execute command

(X), because the memory

pressed. After this command
Use the wake-up command

You can use the C command when you have changed several
you do not want to go back and change each one.
having to cycle the power switch

is

no need to follow the C command with the

is

cleared immediately when ©

is

issued, the DCM-7 returns

(*)to

enter the command receptive mode.

to

off-line mode.

parameters and

It

also saves you from

OFF and ON.

is

D,

d

Use this command

enter the D command, the dialer memory

Enter dialer programming mode

to

enter the dialing parameter setting mode. When you

is

cleared and the DCM-7 waits

for the following subcommand entries:

0-9,

*,

# (Telephone number and code)

These must be valid digits that can be dialed

on

the phone. The * and #

are used only in the touch-tone dialing mode for special service.

P,

p Dial pause subcommand

Wait here for 2 seconds before dialing the rest

to

to enter this command

behind a

R,

PBX.

r

Pulse (rotary) dial subcommand

access an outside line when your phone is located

of

the digits. You may need

Sets the DCM-7 to pulse dialing mode.

33

Tandy protocol reference

T,

t Touch-tone dial subcommand

Sets the DCM-7 to touch-tone mode.

(,),

-,

<space>

Enter these symbols
are

i~nored

by the dialer routine, but are accepted and stored in the dialer

to

make the phone number easy

memory.

to

read. These entries

BS

The

BS

code
typing a number and make an error, press
typed.

If

BACKSPACE

is

simply

an

code

editing feature for the D command.

@ID

to delete the last character

If

you are

you press @[) immediately after .selecting the D command, a ?

will appear to indicate an error condition.

of

up

to

40

A total

and

stored
until you

dialed by the DCM-7. The stored number will be kept in memory

turn

digits and symbols that follow the D command can be

off

or reprogram the DCM-7 by entering

Dor

C. Use the list

command to confirm the number.
The pulse dialing mode

dialing mode

of

the previous call

is

the default condition and the Modem applies the

if

R nor T does not precede the telephone

number.

DCM.:7 allows you

The

to

mix signaling types in a telephone number. For
example, the sequence DR234333PPT-(lll)-123-4567 says to pulse dial the
number 234333, pause for 4 seconds, then tone dial the

number 1111234567.

The dashes, parentheses and space are ignored by the DCM-7 during dialing.

If

you have problems when using touch-tone
your telephone line may not be suitable for these modes.
and/or

E, e Echo disable/ enable toggle

This code

the slow dialing rate. Refer to dialing speed commands F and

is

used to disable or enable the "echo" function. When enabled,

and/or

the fast dialing rate,

Use rotary dialing

S.

the echo supplies feedback to your computer's display. When disabled, data

you send to the DCM-7 will not be echoed to the computer display, includ­ing the parameter settings. The display will not show anything, even
type

L.

If

the echo feature

is

tually it

working normally.

The default (power-up) setting

is

disabled, the DCM-7 will appear -dead, but ac-

of

echo function

is

the echo enable.

if

you

34

Appendix

A

F, f

When you want to tone

Fast dialing speed

or

pulse dial using faster signaling rates, you can
use this command. The F command forces the Modem to dial while in the
automatic originate mode
pulses/second (pps)
then show RA TE

for

= F.

Note: The fast dialing speed command

dialing. Fast pulse dialing

at

10

digits-per-second for touch-tone

pulse dialing. The RATE = S line

is

mainly used in touch-tone

is

seldom used. When you experience

on

the listing will

or

20

difficulty in fast pulse dialing, set the rate to slow.

G,

g Forced carrier detect toggle

is

This command

(FCD). When the

used to

FCD

nal to the computer

lights. When the

FCD

the computer when it detects a true carrier signal

turn

on

and

off

the forced carrier detect signal

is

ON, the DCM-7 issues a forced carrier detect sig-

upon

power-up, and the CARRIER DETECT indicator

is

OFF, the DCM-7 issues a carrier detect signal to

on

the telephone line and

lights up the CARRIER DETECT indicator.
The default condition

G command
switch

FORCED

is

disabled when

is

ON, the Modem informs you by showing:

CD

SWITCH IS ON

You can check the status

this command

DIP

of

the FCD at the FCD = parameter listing by us-

is

SW 2

set by
is

ON.

DIP

switches 2

If

you input G when the

and

6.

The

of

ing the L command.
I, i Ring/retry change command

to

This command allows you

change the answer

The I command displays the intermediate menu. When you press

on

n rings

or

retry n times.

Q) , the

DCM-7 prompts:

ANSWER

ON

1-9

RINGS OR

CR

FOR

NO CHANGE =

The cursor (if used) will be positioned after the = sign and await your in­put.

If

you press (ENTER ) instead
that you want to keep the already programmed number
ber between 1 and 9
are not accepted.

or

If

you reply

the ( ENTER ) key

will echo the key (display the key you just entered,

of

typing a number, the DCM-7 assumes

of

rings. Only a

is

a valid entry. All other entries

to

the prompt with an invalid entry, the DCM"7

if

displayable)

and

nuni""

ask

the question again.

35

Tand~

protocol

ref

ere nee

When you correctly respond to the first prompt, the display shows the next

prompt:

RETRY FOR 1-9 TIMES OR CR FOR NO CHANGE =

Here again, only a numbe; in the range 1 to 9
The prompt

is

asking you how many times the DCM-7 should try a telephone
number before exiting the auto-dialer routine. Enter a value
if

you want· it to redial the number.

When your response

is

acceptable, the DCM-7 will return to the command

or

the (.ENTER) key

of 2 or

is

valid.

greater

receptive mode, ready to accept the next command.
The DCM-7 will look for a valid carrier tone from the remote modem.

carrier

is

not detected within

30

seconds, your DCM-7 gives up and prepares

If

for the next try.

L,

1 List command

The list command

The screen

shows:

MODE=
TYPE
F CD = Y
SPKR = Y
ANSW = 2
DTRY = 1

TEST = N

NUMB=

RATE = s s (Slow),

EXIT

= 0

=

A

OF

is

used to review the current state

Table 10. List Settings and Related Commands

Parameter

A (Automatic

o

(Ori€Jinate),

Y (On-line), N (Off-line)

Y (Monitor speaker on), N (Monitor speaker off)
1-9
1-9

Y

(Self-test on), N (Self-test off)

0-9, T (Touch-tone), R (Pulse), ·p (Pause),

space,

Hex code for abort character

*,

F.

),

A (Answer)

#

(Fast)

M (Manual)

of

the DCM-7.

-,

(,),

Related
Commands

M

O,A

G

p

I
I

Q

D

S,

F

@

The parameters or settings shown above are defaulted when the Modem
initially powered up. ·

M, m
The M command

state to manual state. Each

MODE

= x line

and back again, depending

Manual/

is

used to switch the DCM-7 from its automatic (defaulted)

on

automatic toggle

time this command

is

entered, the value

of

thelisting changes from A (automatic) to M (manual)

on

how many times the M command

36

is

used.

is

the

0,

o Originate mode operation

Appendix

A

The Modem will always operate in originate mode when cold-started (initial
power-up).
work, like CompServe. You can also use this mode

Use origipate mode when you want

to

call a time-sharing net-

to

force the Modem to

automatically dial a telephone number for you while in automatic mode.

This code will change the

(originate type modem) while the A command changes the line to

TYPE = x line in the listing

to

TYPE = 0

TYPE=

A

(answer type modem).

P,p

Use this command
speaker.

Since the Modem powers up with the speaker ON, you can monitor

Monitor speaker

to

control the

on/

off

on/off

toggle

condition

of

the built-in monitor

the telephone line signal (dialing tone, ring back tone, busy tone, carrier tone
etc.) through the speaker during dialing mode.
speaker

SPKR = N. Enter ® again

OFF

by entering ® . SPKR = x line in the list setting will show

to

turn it ON. SPKR = N will change to

For

quiet dialing,

turn

the

SPKR=Y.

Q, q

This command forces the DCM-7 to enter the self-test mode
self" when the X command
tell

if

the Modem
lyzes the condition
computer

is

When power
Modem is
reads

TEST=

Self-test command

is

issued. With this feature, you will be able

is

functioning correctly. This self-test neither tests

of

your telephone lines, since

data

transmitted from the

looped back through only the Modem's circuitry.

is

first applied, the listing line TEST = N tells you

not

selected

Y.

to

go into self-test mode. When you input Q, the line

The Modem

is

ready

to

enter the self-test mode

to

"talk

nor

that

upon

to

ana-

exit-

it-

to

the

ing the command receptive state with the X command. You can then test
to see

if

typed characters are displayed

. .

During the self-test mode, the TRANSMIT

on

the screen.

DATA

and

RECEIVED

DAT

A

indicators flash almost at the same time everytime you input characters.

0

and

To exit self-test mode, input the abort code CTRL
OFF LINE.

To

return to command receptive state, enter the wake-up com-

the Modem goes

mand*.

37

Tandy protocol ref

S, s Slow dialing speed

The

slOw

dialing speed command

telephone number with slow timing (RA TE

==

S). Slow dialing speed

mode, the Modem pulse dials

ere

nee

is

the default

at

10

is

used to force the DCM-7

==

x line on the listing reads RA TE

at

power-up. While in slow speed

pulses per second and touch-tone dials

at 5 digits per .second.

X, x Execute programmed comm.and(s)

This command signals the DCM-7 that programming
time

to

go ON LINE (off-hook) and execute your fnstructions. When the

X command

is

received, the Modem will do one

is

completed and it

of

three things:

1. Enter a waiting state and monitor the telephone lines for

call (auto-answer

2~

Seize the telephone lines
or

manual answer mode)

mode).

and

monitor for carrier (if in manual originate

or

start the dialing sequences (if in auto-originate .

mode).

3. Enter the self-test mode in the

TEST=

Y condition.

to

dial any

an

incoming

is

38

Hayes protocol ref ere nee B

Programming commands

AT Attention code
Every command line starts with the attention code. Always enter this code

in uppercase letters.
letters.

Other commands may be typed in lower- or uppercase

CR
Ends the command line. The Modem does not execute a command until you

press (
To redefine it, change the value

BS
You can edit a command line with the

the beginning
as

ENTER ) • The carriage return key

08

in ASCII value.

Carriage return

is

defined as

of

register S3.

Backspace

@ID

key,

of

a command line cannot be deleted. The @ key

To

redefine it, change the value

13

but

the attention code

of

in ASCII value.

at

is

defined

register S5.

+ + + Escape code

Use the escape code
you input escape code
displays the result code OK. The telephone line will remain connected until
you input

The escape character can be redefined with register
the escape character, do
the data line.

The escape code
time
of

the escape code.

code. As a result, the escape code

The escape guard time can be redefined with register
is

50
at least 1 second, input
command line. Without the guard time, the Modem cannot recognize the
escape code.

To return

HO

is

inserted between the last character transmitted and the first character .

(1

second). When entering the escape code with default values, wait

ON LINE, enter ATO (

to

return to command mode from

+ + + , the Modem returns

(ON HOOK command) or Z (Reset command).

not

select characters which are frequently used in

is

marked

off

from data by the escape guard time. This guard

It

is

also inserted after the third character

is

sandwiched by the escape guard time.

ON

LINE. When

to

command mode

S2. When you redefine

of

S12. Its default value

+ + + , then wait 1 second more before entering the

ENTER)

•

and

the escape

39

Hayes protocol reference

A, a Manual answer command
When the A command

for the carrier signal.

Use this command

entered, the Modem goes

to

begin computer communication

OFF

HOOK and waits

is

immediately after talking with a friend by phone. In this case, one user should
input A while the other
after A will not be executed.

commands before the manual answer command.

the

uses the dial command D. Any command placed

If

you want to execute other commands, insert

Example:

AT

F1

A (

ENTER

)

Wak9-

up!

S9-19-Ct

full

dupl9-X.

Wait for

a·

carrier tone.

D, d

The D command sets the Modem to originate
phone. D

can

Autodial command

a call without using a

be followed by the dialer codes shown in Table

11.

When used

tek-

alone, D sets the Modem to auto-originate mode.

Table 11. Dialer Codes

Codes

0-9

(,),

-,

SPc::lC9-

*, #

p

T

R

, (comma)

(semicolon)

;

Used for the telephone number. .
Us9-d

to make the telephon9­Used only in touch-ton9­Sets the Modem
Sets the Modem to
Cht:mQ9-S
mod9­S9-tS
after
Returns

the Modem from originate rnode to

onc9-

communication is 9-Stablish9-d.

the

Modem

th9-

c::lCCess

the

code). -

Modem to

Function

number

dic::lling

to

puls9-

dialing mode.

touch-ton~

to

Pc::lUSe

commc::ind

dialing mode.

while

rec::idable.

mod9-.

an~wer

dic::lling

(can be

mode after dialing.

U!)9-d

Example:

AT

DT(111)123-0009 (ENTER) Wake up!

call

by

Originate a

touch-tone dialing.

After dialing the number, the Modem waits for a carrier sigqal. When a carrier

is

not

detected within a time set by register S7,. the Modem automatically

releases the line and sends the result code:

NO

CARRIER (or

3)

40

Appendix

B

When a carrier signal

is

detected, the Modem goes

ON

LINE and sends the

result code:

CONNECT (or

The result code

Switch 4). The type

3).

1)

ON/OFF

of

the code

condition

is

determined

is

determined by the V command (DIP Switch

by

the Q command (DIP

R, r Reverse mode command
Use this command

only modem. When R

to

call and establish communication with

is

entered, the Modem enters answer mode

an

originate-

automatically after it dials the telephone number.

Example:

AT D(111)123-0009R (ENTER) Wake up!

Originate a call.

Change
carrier.

P,

p Pulse dialing (default)

The P command sets the Modem
is

rotary type, input P at any point in the telephone number sequence. You
can change
ATP

When the type

to

pulse dialing mode from touch-tone dialing mode by entering

any time you want.

of

dialing (pulse
mand line, the Modem defaults
dialing

is

fixed at

10

pps (pulses per second).

to

or

touch-tone) is

to

the type used in the last command. Pulse

to answer mode and wait for

pulse dialing mode.

not

specified in the com-

If

your phone line

T,

t Touch-tone dialing

When T is added

ing mode.

to

the dial command, the Modem is set

Use register

Sll

Pause

When you use the Modem in

to

get

an

code
dialing the number
code

and

The pause duration
of

I comma

outside telephone line, you will need

that

follows. Insert the , command between the access

the telephone number.

is

determined by register S8. The default pause duration

is

2 seconds. You can accumulate the duration by using multi-

ple commas.

to

change the speed

an

office

or

41

of

anywhere

to

touch-tone dial-

touch-tone dialing.

that

to

requires

add

an

access

a pause before

Hayes protocol reference

Return the Modem to command mode

Place this command code

mitting information

nizes touch-tones. By inserting the semicolon, you can

at

the end

to

a telephone order service

of

the dial command line when trans-

or

bank service

ent~r

a long command

line before establishing communication with another modem.

Example:

The screen

shows:

AT D T(111)123-4567; (ENTER) Wgke up!

OK

AT D 43278

OK

AT 08881

OK

AT

OK

AT

D

273*65#;

HO

(ENTER)

Command

#;

(

ENTER

#;

(ENTER)

(ENTER)

line

)

Function

Originate the call by touch-

ton~

dialing.

Return to command mode.

Tr?nsmit the ID number.

R~turn

Tr?nsmit the password.

Return to command

Ent~r

Return to command

Terminate the call.

to command

the transaction.

that

recog-

mod~.

mod~.

mod~.

Al

Repeat the command line (Redial command)

The Modem repeats the command line stored in the command buffer when

. repeat command

get a busy signal or

A/

is

entered. Use this command to dial again when you

if

a carrier signal

is

not detected. There

is

no

need to
input the attention code AT or carriage return before or after the repeat com­mand. Just enter

The command buffer

• New command line beginning with AT

• Reset command Z

• Modem

O,

o On-line command

A/.

is

cleared under the following conditions.:

is

is

switched OFF

entered

is

entered

The on-line command returns the Modem to on-line mode from command
mode (reverse

of

the escape command). Use this command to return

to

the

on-line state after executing the local command.

42

Appendix

B

Z, z Reset command
This command clears the DCM-7 command buffer and resets all commands

and registers to the default values. When you have changed the commands

to

and registers from default condition, use this command
default settings.

It

will save you from cycling the power switch OFF and ON.

return to the

E, e Echo command

is

This command
El

to echo the command line to verify that the Modem

ing the commands sent

used to disable or enable the command echo function. Enter

is

to

it. Enter

EO

when you do

accurately

not

want to echo the

receiv'"

command line.

is

When the echo feature
actually it

DIP

by
the switch

is

working normally. The default setting

switch. For example,

is

ON, the default

disabled

if

is

(EO),

DIP

EO.

the Modem will appear dead,

of

this command

switch 5

is

OFF, the default

is

is

El.

but

set

If

F, f
Selects full- or half-duplex communications mode.

Full/half

duplex

Fl

sets the Modem to com­municate in full-duplex mode that only echoes received
(default).
echoes both received

Q,

Determines whether the result codes will be sent

display result codes

FO

sets the Modem to communicate in

and

transmitted data

q

Result codes

and

Q 1

ON/OFF

if

the codes

command

are

half

to

the display during

to

the screen. Enter

not

to

V, v Result codes mode selector

of

Selects the type
VI

is

for verbal codes.

result codes displayed.

Note: The default values

of

commands Q

VO

is

used for numeric codes

and

V are set by

switches.

C, c Transmitter
The C command sets the Modem's transmitter

When

Cl

is

entered, the transmitter

ON

when the Modem originates

modem.

Otherwise, it

is

ON/OFF

OFF.

command

is

switched ON. The carrier signal

or

answers a call

·carrier signal
or

data

when

ON

LINE

duplex. The Modem

ON

LINE.

QO

be sent.

DIP

ON

or

OFF.

connects

to

the remote

to

and

is

43

Hayes protocol reference

When

CO

is

entered, the transmitter

Cl

or

reset command Z
Modem does
rier tone during originate mode operation ..

to

Data

H,

h

Controls. the hook switch
the condition
is

not

in use.

line

is

Use

the

the

Modem

M,

m Speaker Control

Controls the built-in speaker.
You can monitor signals
tone, busy signal and carrier tone. The speaker turns
recognizes

When you want to continue monitoring
instead
at

all.

not

issue carrier even when it detects the answer modem's

line monitoring mode operation later. in this chapter.

Hook

of

the handset resting

In

the

in use.. ·

HO

setting for normal operation. When originating or answering calls, ·

controls

a· carrier signal and sends a CONNECT result code.

of M 1.

Or, input

is

entered. As long as the transmitter is OFF, the

switch control

of

Hl

setting, the handset

off

hook condition automatically. ·

on

the telephone line such as a dial tone, ring-back

MO

is

switched

a telephone.

on

Use

Ml

(defa:ult)

if

you do not want to use the speaker function

The

the

is

the

OFF

For

further information, refer

HO

hook

off

the hook and the telephone

to

monitor a call in progress.

data

and remains OFF until

car"'

setting

while the telephone line

communication, use M2

is

comparable to

OFF when

the

Modem

Registers

SO

The value

before the

0

to set the Modem to auto:-answer mode.

will

not
prescribed syntax (refer to Command syntax, in Chapter
value when you use the Modem in auto-answer mode.

When

DIP

with

SO=

swer mode immediately.

Sl

The value
occur within about 8 seconds

· value

of

Defines the rings for answering a call

of

register

Modem answers a call. Input any decimal number greater than

answer a call.· Since the default value

Switch 6

1.

Answer command A disregards the

of

Sl

SO

is

SO

determines the number

is

OFF, the Modem will power-up in auto-answer mode

Counts the rings

increases each time the phone rings and clears

of

the last ring. This will operate only if the

greater

than

0.

44

If

the value

of

times the phone will ring

is

of

SO

is

SO

value since

set to 0, the Modem

preset

at

0, use the

3)

to change the

it

enters an-

if

no rings

Appendix

B

S2

S2

stores the ASCII value

is

set to

the

Sx = n syntax. The value must be a decimal number in the range 0 to

127.

If

you enter a value out

S3

S3

stores the ASCII value

number in the range

function key. The default value

S4 Line feed code definition

S4

stores the ASCII value

as

10

(default). You can redefine the value by inputting the new ASCII charac­ter code as a line feed function key. The character
return only when the verbal result code
be a decimal number

SS

S5

stores the ASCII value
(decimal)
between

Escape code definition

of

the escape code character. The default value

43

( +

).

To

change the escape function key, change the code using

of

Carriage return code definition

of

the carriage return character. Enter a decimal

0

to

127

when you want

of

the line feed character. The value

in

the range 0 to 127.

Backspace code definition

of

the backspace character code. The default value

is

set

to

8.

To

change the backspace function key, select a value

0

and

32

or

127. These numbers do

this range, the escape will be disabled.

to

change the carriage return

is

13.

is

predefined

is

output

is

supported (Vl). The value must

not

include printable ASCII

after the carriage

characters 33-126.

S6

Register

is

defined as the length

Dial

tone

wait time definition

S6

determines the wait time for receiving a dial tone. This wait time

of

time it takes

to

input

the

first digit

of

the phone
number after you pick up the telephone receiver. The default value
at the minimum wait time
change the wait time, input the number
than 2 is

programmed into S6, it will still wait for 2 seconds.

of

2 seconds, which

of

is

regulated by the FCC.

seconds you want.

If

a value less

is

set

To

S7 Carrier tone wait time definition

The carrier tone wait time

is

defined as the length

of

time the Modem can
wait for a carrier tone transmitted from the remote modem. The value
S7

determines this wait time.

the restricted time, it hangs up and displays result code

3 when
30

QO

seconds.

is supported, then returns

To

change, input the number

Once the carrier tone is detected, the Modem displays CONNECT

ON

it goes

LINE.

If

the Modem cannot receive a carrier tone within

NO CARRIER

to

command mode.

of

seconds you wish.

It

is

defaulted to

or

45

1 and

of
or

Hayes protocol reference

S8
To

access
service, the
of

register

conds, it can be changed

S9 Carrier detect response time definition

The value
the Modem
increases, the possibility
The default value
To

change it,
DO

NOT

SlO

Register SlO decides how long the Modem waits
necting the line.
time fixed by the

you

When
present
fo.put

Sll

and

the

The value
tone dialing. The default value
sets the dialing rate
per second can be obtained
mum

value for reliable dialing

Register

Pause

an

outside line through a

comma(,)

SS

determines pause duration for this comma. Defaulted

of

register

takes

input

(,)

duration

is

used

by

S9

determines the length

to

recognize the carrier tone and go

of

of

S9

is

set

definition

PBX

or

when using a special telephone

to

pause after dialing

inputting the desired number

of

detecting a false carrier from noise decreases.

at

6 with the unit

the desired duration times 10.

an

time (carrier duration) which

ON

of

1/lO

confuse S9 with the carrier tone wait time definition, S7.

Carrier

loss time definition

for

When

the Modem does

not

receive a carrier

SlO value, it disconnects the telephone line.

set the value

ignores carrier detect.

desired number

Touch-tone dialing speed definition

of

Sl

1 defines the duration and spacing

to

255, the Modem assumes the carrier

It

is

defaulted to 7 (0.7 seconds).

of

seconds times

of

Sl

to

7.14 digits per second. The dialing rate

1

is

70 in units

10.

of

the tones during touch-

by applying the value 100 (50)

is

50

and

the maximum value is 255.

Sll

does

not

affect the pulse dialing speed; it

access code. The value

to

2 se-

of

seconds.

LINE.

As

the value

second (0.6 seconds).

carrier before discon-

tone

within the

is

always

To

change,

·

of

milliseconds. This

of

5 (10) digits

to

Sl

1.

The mini-

is

fixed

at

10

pps.

S12 Escape code guard time definition

The value
time
The default value

of

S12 determines the escape code guard time. This escape guard

is

specified

to

Note: Beware

greater

20 minimum

is

50,

that

that

the small guard time you assign should be

than

the time required to transmit one

and

255

maximum

is, 1 second.

cape characters. .

46

in

units

of

of

1/50

the 3 es-

second.

Appendix

B

S16

The self-test mode forces the Modem to
S16

when you want to set the Modem to self-test mode. Using this feature,

you will be able to tell
When the Modem

that

data transmitted from the computer

processed just as

Self-test toggle

"talk

to

itself." Apply value 1 to

if

the Modem

is

in self-test mode, the internal switches are selected such

if

it were in communications over the telephone lines. Keys

is

functioning correctly.

is

looped back to the receiver and

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.

To set the Modem for self-test mode in answer mode, type:

AT S16=1 A (ENTER) Self-test mode ON.

Answer mode.

47

Hayes protocol reference

Data line monitoring

The DCM-7 can be used to monitor a
the figure below. To accomplish this monitoring
transmitter should be turned

off

ignored.

"For originate mode, input:

AT

CO

810

= 255 D (ENTER)

For

answer mode, input:

AT

CO

$10 = 255 A (ENTER)

bps

Computer

300
modem

DCM-7

data

and loss

line up

of

to

300 bps as shown in

mod~;

the Modem's carrier

carrier condition should be

Computer

Terminal

48

Connecting the DCM-7 C

Your DCM-7

via a

modular

faces directly with RS-232C-equipped Tandy computers.

is

Bell System

connector. The RS-232C

103

compatible, connecting

input/

output

to

of

Telephone connections

Please

note

that

each product connected

tain

load

on

the line. This is designated as the

Number."
When

using more
lence numbers.
areas a
local telephone company.

The
the

Warning:

• Coin-operated phones

• Party-line phones
The

phone
mode only, you

Single-line

total

registration

bottom

The

way you connect the DCM-7

is

connected

1. Remove

it

in

the

2. Plug the

jack.

than

one product

If

they total more

of 3 may

of

the unit.

Modem

your

PHONE

Modem's

impair ringer operation.

number

must

to

the wall.

do

not

need

telephone's plug from the

jack

WALL

than

as well as ringer equivalence number appears

not

be connected

to

(If

to

use a telephone.)

on

the rear

JACK

to

the telephone line places a cer-

unit's

on

the line,

5, your

a telephone depends

you plan

of

phone line

phone

To

to:

to

use

modular

the

Modem.

total

be sure, check with your

the

cord

"Ringer Equivalence

all the ringer equiva-

may

DCM-7 in automatic

wall

into the

the telephone lines

the

not

on

jack

Modem

ring.

how

modular

In

your

and

inter-

rural

on

tele-

insert

wall

Figure 6. Modular Telephone Connection

49

Connecting the DCM-7

If

your telephone has the older style, four-prong connection, use

(Radio

Shack Cat. No. 279-360)

to

connect it

to

your DCM-7 as shown in

Figure 7.

an

adapter

Figure 7. Connection to a Four-Prong

If

your telephone

is

wired directly

to

the wall, the jacks and adapters neces-

sary for the conversion can be purchased from your nearest Radio

Jack

Shack
store. Or, you may contact the telephone company to have modular connec­tions installed.- The telephone company

of

installation
is

RJ-llC.

such jacks. The

U.S.0.C.

is

authorized

to

charge you for the

number for the plug connection

Multi-line
The DCM-7 Modem can be used with a multi-line telephone,

but

you may
need a multi-line adapter (43-271), a hardware modification to the Modem,
or both.

If

you use a multi-line adapter only, the HOLD button
can interfere with communication
pro bl em, have a qualified Radio

Radio Shack has several adapters
to multi-line telephones. Contact your Radio

if

someone presses it. To avoid this

Shack service technician modify the DCM-

that

can be used for connecting the DCM-7

Shack Computer Center or store

on

an extension phone

7.

for details.

50

Appendix

Computer connections

The DCM-7 uses the RS-232C standard serial interface cable
your computer. The table below provides the cable requirement for
computers.

If

more detailed information

is

needed, refer

owner's manual.

Table 12. Modem-to-Computer Cables

Computer

Model 1
Model

11/16

Model lll/4/4D/4P/12/16B/16B HD

DT-1/DT-100/100

Tandy 102/200/600/1000/1200/1200HD/2000/6000

Tandy 3000

Cable Catalog No.

to

connect

to

your computer's

26-1145
26-4403

26-1408
26-1408
26-1399

C

to

Tandy

1. Plug the appropriate end

dard DB-25 jack

2.

Plug the other end

on

of

the interface cable into the

the rear

of

the cable into the computer's DB-25 jack.

of

the Modem.

R~-232C

stan-

For the following computers, you'll need option boards which contain
RS-232C interface

to

connect your DCM-7. Contact your Radio Shack Com-

puter Center for details.

Table 13. Computer Option Boards

Computer

Model I
Tandy 1000
Tandy 1200

RS-232C Interface Board with cable
RS-232C Option Board

Captain Multifunction Board

Board

Catalog No.

26-1145
25-1006
25-3061

Power source

Insert the
Modem.
er strip.

Be

sure to connect the adapter

into the wall outlet. Otherwise, damage

AC

adapter's plug into the

Plug the adapter into

an

to

AC

power jack

electrical wall outlet

the Modem before you plug the adapter

to

the adapter could result.

Note: Use the supplied adapter only. Another type

damage the Modem.

on

the rear

or

an

approved pow-

of

adapter could

of

an

the

51

·

....

XENIX

operations D

Your DCM-7
operating system (Version 3.1
plaining how using the DCM-7 with XENIX differs from operations in other
modes.

is

configured to operate with a Tandy 6000 running the XENIX

or

later). This section will be helpful

in

ex-

Always automatic answer mode

Set the
on
the telephone
is
the Modem
operation.

DIP

switches as illustrated and power up the DCM-7.

condition, the DCM-7

line for

asserted (this happens when log-ins are allowed using the enable command),

will pick up the call and assume always auto-answer, 10-bit word

will

power up into the call-waiting state and monitor

an

incoming call. When

DTR

(Data Terminal Ready)

From

a power-

Dial out

Set the
mode operation
matically

Refer

ing a modem with XENIX.

DIP

switches using the same settings as in always automatic answer

and

dial a call by using the command:

dialHAYES ( ENTER)

to

your

XENIX

power up the DCM-

system's documentation for more information

7.

Program the Modem

to

auto-

on

us-

53

Troubleshooting E

When you have problems transmitting
rors, etc.), there are a few checks you can make before taking the unit
a Radio Shack service technician:

• Phone connection

• No one is talking

• Phone

• Operation speed

The only maintenance your DCM-7 requires is a periodic checking
and

connections. When you experience
the cable connections. Then run the self-test.
check with your Radio Shack Computer Center

Precautions
Lightning.

that

meet

in telephone line current. However, an incident such

or

directly to, the telephone line may cause

can damage the phone device. Lightning damage

cur

to
live in
that

you unplug the electronic products during storms.

It

is

very unlikely
the telephone company has the right
ice.

If

this happens, the telephone company will notify you
chance
right

to
fect your DCM-7
will notify you
uninterrupted service.

and

all extensions are

Your Radio Shack phone product has built-in protection circuits

or

exceed

phone

and

other electronic devices.

an

area with frequent

...

to

have the problem corrected. Also, the telephone company has the

make changes in their lines

or

in

writing so

is

clean and noise-free.

on

the telephone line.

is

300.

FCC

requirements

and/or

but

if

your DCM-7 causes problems

require changes in its connection, the phone company

that

data

(garbled data, intermittent er-

on

hook.

of

data

transfer problems, first check

If

you still experience problems,

or

store.

to

reduce risk

an

If

severe electrical storms, it is suggested

to

temporarily discontinue your serv-

and/

or

equipment.

you can take the necessary steps

or

damage from surges

as

a lightning strike near,

excessive surge

is

uncommon,

you are concerned

of

on

the phone line,
and

If

these changes af-

voltage

but

about

give you a

to

cables

can oc-

it

ensure

to

that

or

Analog loop self-test

When you cannot locate the source
the Q command (or
data

sent from your computer
you know whether the Modem
test does

not

test nor analyze the condition

S16=1

in Hayes protocol mode). This test causes the

to

be looped back

is

functioning properly. The analog loop self-

of

your problem, test the Modem with

to

the receiver, thus letting

of

your teiephone circuits.

55

Troubleshooting

Multi-line phone operation

The DCM-7 Modem has an internal configuration option which allows the
Modem to be used with multi-line telephones. This option must be performed
by a qualified Radio

With this option, the internal circuitry can be configured to signal a local
network that there
the Modem
BUSY indicator

is

modified internally, the local network will start flashing the

Shack service technician.

is

a MODEM

on

the multi-line telephone when the Modem seizes the line.

on

the line instead

of

a telephone. Unless

56

Performance

Operation modes

Receive frequencies

Answer
Originate

Transmit frequencies

Answer

Originate

Transmit level
Receive sensitivity
Carrier detect sensitivity
Baud rate
Output
Telephone dialer (auto-originate mode)

impedance

Pulse dialing

Touch-tone dialing

(Tandy /Hayes)

Physical/

Electrical requirements

Operating temperature
Humidity

Operating environment
Storage

(NO ERROR)

environmental

Specifications F

Tandy
Hayes protocol
Full
Automatic answer
Manual answer

Mark
Space 1070
Mark
Space 2025

Mark
Space 2025
Mark
Space 1070

300 bps
600 ohms

Dialing rate (slow),
Breaking ratio (slow),
Interdigital pause (slow),
820 mS
Duration
100
Interdigital time (slow),
100

15

AC
55°F-85°F (12.8°C-29.4°C}

900/o
condensing) ­900/o

protocol

or

half duplex

I originate

1270 Hz

Hz

2225

Hz

Hz

2225

Hz

Hz

1270

Hz

Hz

-13

dBm

-35

dBm

-40

dBm

of

signals (slow),

mS/70
mS/70

VAC@

adapter supplied

mS
mS

600

mA

relative humidity (non­(non-condensing)

I originate

10 pps

600/o

57

Specifications

Dimensions (H x W x D)

Weight

1-3/4"

x 6-7/10" x

(45x170x260

24 oz (680 g)

10-1/4"

mm)

58

~~~~---------

~-11=

00

~

=-

Vl

\0

~

e

flllllt-.

=

••

~

NOTES:

(I ) ALL

RESISTANCE

(2)

ALL

CAPACITANCE VALUES

*

THE

JUMPER

OTHERWISE SHOULD

~:1::

r-==----------

_____

VALUES

ARE

IN

OHM

( K •

103 OHM,

ARE

IN

pF

WI

IS

USED

BE

OPENED.

FOR

MULTI-LINE

( P •

10-1 pF

PHONES

l.

M • 10•

AND

1 DIPSW TANDY PROTOCOL HAYES PROTOCOL

_J

N~-

FORCEOO~TR

TRUE

::

FORCED

NO

FUNCTION

INC

FUNCTION

OHM

).

NO FUNCTION INO FUNCTION

NO

FUNCTION

6

lNO

FUNCTtON

IVERIAL

fNO

(COMMAND

j I

'>~

D~=

TRUE

DT~FF

RESULT

CODES

I

NUMERIC

RESULT

RESULT CODES ISENO RESULT CODES

ECHO

OFf

!COMfi&Fi.ND

ECHO

HAYES PROTOCOL

CODES

. _ _J

This schematic is subject

ON

For the most accurate schematic (and parts) contact
Radio Shack, National Parts Dept., Fort Worth TX

76102.

to

change without notice.

Q..

••

=

~·

=

e

~

Index

Abort

character
Aborting the on-line mode
Analog loop
Answer mode, for Hayes

protocol..

programming of.
DIP

Answer mode, for Tandy

protocol..

automatic
manual..
DIP

Attention code
Autodial command, for Hayes

protocol..

Backspace code

for

Hayes
redefining
for Tandy protocol.

....................................

Bps

Carrier detect .. 3, 6-8, 17, 24, 45-46

loss time, redefining
indicator
response time,

redefining

wait time, redefining

Carriage return

code definition, in Hayes

protocol.

See

al110

the value
Carrier tone
Carrier tone wait time
Clear memory command

Command

clearing

Command

programming in Hayes

protocol.

table

...

15, 18, 31,' 32, 36

.............

.................

switches, settings

..............

...........

.............

switches, settings

...........

..................

....................

............................

............................

registers, changing

..............

buffer,

of..

........................

codes

of

............................

17, 37, 47,

...............

5-7, 9, 14,
11, 15-16,

11, 14-15, 36

9, 21, 23, 39

..............

protocol..

............

.......

.................

...................

14, 18, 45-46

...............

............

.........

32-38, 39-47

....................

.....

18-19

7-8, 23,

of..

... 7-8

of..

...

5-7

21, 23, 40

23, 39,

......

23, 39

24,

8,

24,

24,

......

24,
23, 39

45

33

.43

21-22

23

55

40

.40

33
18

45

45
34
57

46

3

46
45

45

parameters, table
programming in Tandy
protocol
table

Command
Command
Command
Commands with parameters
Communications protocol.
Connecting the computer

optional boards

Connecting
Connecting

single-line connection
multi-line connection

CTRL 0 .......................

Data

indicator

loss
Dialer codes
Dialer programming mode
Dialing speed
DIP

switches, setting

for Tandy protocol,

for Hayes protocol,

Echo disable/enable

for Hayes protocol.

for Tandy protocol..
Electrical specifications
Environmental specifications
Escape code

redefining

Escape guard time
Execute command

Fast dialing speed
Forced carrier detect.
Forced

........................

of

............................

mode, returning
receptive state

syntax

to

a power source

to

the telephone .. .49-50

terminal ready

............................

of

...............................

................. ; .....

......................

table

of

...........................

table

of

...........................

.......................

.........................

data

terminal ready

of..

......

.....................

...........

..................

...........

15, 17, 32

...................

of..

..........

.........

.........

...........

..............

...............

....................

................

......

6-7, 8,

..........

11-17

to

....

12, 32

.......

...........

.....

.....

.49-50

3 3, 40

.........

35,

7, 34,

7,

...

57-58

23, 39

39,

35, 36

......

6, 8

22

31

.42

25
22

8
51
51
51

50

6
3

18

33
38

5-8

6

8

43

43

34
57

45
46
38

35

61

Index

Full duplex

Half

Hayes protocol..

Hook

Line feed code
Logging
Loss
Loss

Maintenance
Manual mode

operations

Multi-line telephones

Numerical result

codes

Off-hook indicator
On-line command
On-line mode, aborting

.............................

duplex ....

changing the register

value

checking the register

value
dialer codes
DIP

table
programming

commands
registe,r commands
registers
result codes
sample programming

session

switch control.

of

of

answering the phone
making a call..

configuring the mode,m
connecting the

loss

_.

........................

........

39-48

.............................

.............................

.......................

switch settings,

of

...........................

........

...................

.......................

...........................

...............

.........................

on

....................

carrier

.........................

data

terminal ready

............................

..................

...................

............

mode,m

......................

.....................

....................

of

carrie,r

....................

.43

43

7-8, 9, 21-28,

25

25
40

22-23, 39-44

..........

24-25

24, 44-47

26

21

.44

45

13, 26-28

18

........

18

55

11,

36,

40

.......

14-15

15

50,

56

........

56

.........

50

7, 8, ·22,

.............

26

.42

18
18

loss

of

data terminal ready ...
receiving a long space
transmitting the

character

Originating a call

Pause. command, in Hayes

protocol.

defining the duration

Pause, flag, in Tandy protocol.. ...

Performance specifications

8

3

Phone

ja~k

Power jack
Power source
Programming commands See

command codes

Pulse dialing

Received
Registers

changing the value

checking the value
Repeat command
Reset command
Result codes

for Tandy protocol..
for Hayes protocol..
mode selector
ON/OFF

Reverse mode
Ring/retry
Rotary dialing See pulse dialing
RS-232C cables, for connecting the

modem

RS-232C standard

DB-25 jack

Schematic
Self test mode

programming in Tandy

protocol..

..................

.....................

..............................

......................

.........................

...........................

...................... 3 3,

data

indicator

....................

......................

.......................

....................

toggle

..........................

....................

to

a compute,r.

......................

...............................

...............

............

..........

abort

.........

...............

24-25,

..............

..............

...........

....

................

16,

...........

17, 37,

17, 37,

18,

.........

: .. .4,

.4,

44-47

7, 8,

17,

.4,

18
19

32
37

41

.46

33
57
49
51
51

41

3

25
25
42

.43

19
26
43

.43

41

35

51

51

59
55

55

62

programming in Hayes

protocol..
Slow dialing command
Specifications
Terminal ready indicator
Touch-tone dialing

redefining the speed
Transmit
Transmitter carrier signal.
Trouble.shooting
True carrier detect.
True

data

................

.......................

.........

data

indicator

.......................

.................

terminal ready

..............

...............

.47,

57-58

.............

23, 34,
of

.......

.........

6, 8

.........

6, 8

Index

55

38

3

41

.46

3

.43

55

Valid dialer codes
Verbal result codes

Wake-up command
Wall

jack

...................... ; ....

Wait for ring, changing the value

of

.......................................

XENIX

operating systems
answering the phone
making a call

............

.....

......................

33-34,

8, 22, 26,

.....

9, 11, 18, 32

..........

...........

.4,

40
43

49

44

53

53

5 3

63

SERVICE POLICY

Radio Shack's nationwide network of service facilities provides quick, conveni­ent, and

reliable repair services for all TANDY/Radio Shack computer products,

in

most instances. Warranty service will
Shack's Limited Warranty. Non-warranty service will
parts

and

labor costs.

Because of the sensitivity of computer products,
result from improper servicing, the following limitations also apply

vices offered

1.

If any of the warranty seals
ucts
the product or

2.

If any computer product purchased from Radio Shack has been modified so
that
the
boards, then Radio Shack reserves the right
void any remaining warranty, remove. and
found
return the product

3.

The cost for the labor and parts required
original manufacturer's specifications will
dition

by

Radio Shack:

it

sells are broken, Radio Shack reserves the right to refuse

to

void any remaining warranty

it

is

not within manufacturer's specifications, including, but not limited to,

installation of any non-Radio Shack parts, ·components, or replacement

in

the product, and perform whatever modifications are necessary to

to

original factory manufacturer's specifications.

to

the normal repair charge.

be

performed

on

any Radio Shack and Tandy computer prod-

be

in

accordance with Radio

be

provided at reasonable

and

the problems which can

on

the product.

to

refuse

replace any non-Radio Shack part

to

to

return the computer product to

charged

to

to

to

service the product,

the customer

the ser-

service

in

ad-

•

•

•

•

.

~·

"

.

•

'

.

.

•

•

CUSTOM MANUFACTURED FOR RADIO SHACK

A Division

FORT WORTH, TEXAS 76102

•

of

Tandy Corporation

..

Printed in

Taiwan

5A6

811017400A