Datatronics ITU-T V.42bis Getting Started Manual

_______ GETTING STARTED MANUAL _________

If you will use this modem with a personal computer and a popular
off-the-shelf communications software, for a simple modem application
such as going on-line with bulletin boards, up-loading or downloading
files, and sending fax messages, you may now go to the Getting Started
Manual to exercise hardware connection for your modem. Then, you
should refer to your software’s manual to get on the road. This manual
will serve as your guide for modem commands.

If you would like to know the modem operations and commands in
more depth, the Electronic Manual of Fax-modem diskette is included
to serve this purpose.

The LED Indicators on the Front Panel _______________________

The indicators on the modem’s front panel denote the current modem
operation characteristics and status. They are:

MR M

odem Ready. Lights up when the modem is turned on.

TR T

erminal Ready. Flashes when DTR signal is detected.

CD C

arrier Detected. Lights up when a carrier from the remote

modem is detected.

SD S

end Data. Flashes when the modem is sending data to the

remote modem or when receiving data from the local computer.

RD R

eceive Data. Flashes when the modem is receiving data from

the remote modem or when sending data to the local computer.

AA A

uto-Answer. Lights up when the modem is set for auto-answer.

Flashes when an incoming ring is detected.

OH O

ff-Hook. Lights up when the modem is using the telephone line.

Off when the modem hangs-up (on-hook).

HS H

igh Speed. Lights up when modem speed exceeds 4800 bps.

When you turn on your modem, at least the MR indicator shall light up.
There may be some other indictors lights depended on the settlement of
the modem. Otherwise, you should check the power connected to your
modem.

Page:1

The Rear Panel and the Connectors __________________________
PHONE ：Accepts a telephone set connected parallel to your modem.

LINE ：Accepts the RJ-11 cable that links your modem to a

telephone line or to a 2-wire leased-line.

RS-232 ：Accepts the serial cable that is connected between your

modem and your computer.

12VAC ：Accepts the power adaptor that comes with your modem.

Power Adaptor

Power Switch

To Serial Port on
Your Computer

Connect to
Telephone Line

Connect to
Telephone Set

VR

MIC

SPK

The Serial Port and the RS-232 Cable_________________________

To use this modem, it will require an RS-232 serial port on your
computer. If your do not have it, you need to have one.

It is better to select a serial port card that uses a high-speed 16550
UART chip. A card with an ordinary UART chip handles transmissions
at a maximum speed around 38,400bps. In case the data compression of

Page:2

your modem is active, it may perform at an exceeding speed and an
ordinary serial port card may sometimes cause data loss.

You will also require an RS-232 cable to connect your modem with
computer. You will be Asked to buy a modem cable if you are a PC
user. The modem cable shall, at one end, have a DB25M (male)
connector that fits the female connector on the modem, and at the other
end a serial port connector that matches your computer.

Hardware Connection______________________________________

1) Make sure that both the modem and computer are turned off.

2) Use an RS-232 cable to connect the modem to a serial port on your
computer. Secure the connector screw on it.

) Verify the serial port number in which your modem is connected.

You must Write down the port number as you will need to specify
this number during software installation. As a general rule on PC
applications, the port COM1 is connected to a mouse, while COM2
is for a modem.

3) Use an RJ-11 cable to connect the LINE jack to the wall outlet of the
telephone line.

4) Connect a telephone set to the PHONE jack. You may leave this
jack disconnected if desired.

5) Make sure that the power adaptor that comes with your modem is of
a correct voltage that complies with your power source. Use the
adaptor to connect the power source to the 12VAC jack on the
modem.

Page:3

Test the Power Connection__________________________________

You can turn on your modem by pushing the power switch button and
watch the front panel indicators. Depending on the setting of your
modem, the MR and other indicators should light up. If none is lit,
check the power connection for the modem.

Test the Telephone Line Connection __________________________

Once a telephone set is connected, you may test the line quality and
connections by lifting the telephone handset, listening for a clear dial
tone, and making several telephone calls. The calls shoud go through
well and the sound loud and clear. Otherwise, the line may be poor or
have a faulty connection.

Data Communications Software Packages _____________________

Your modem follows the industrial standard in the modem command
set. As a result, most of the popular communications software packages
off-the-shelf will work with it. You should select a software package
according to your application requirement.

Most popular communications software are provided with the
configuration named Initial-String or Dialing-Prefix. It is wise to check,
one by one, the commands in this string as they will be sent to
determine the modem characteristics each time prior to dialing.

Fax Communications Software Packages ______________________

Similar to data communication applications, you interact with the
modem through the fax communications software.

Your modem only supports Class 1 command set.

Error-Correction and Data Compression______________________

Your modem supports the industrial standards of MNP 5 and ITU-T
(formerly called CCITT) V.42bis for error-correction and data
compression (ECDC). Both standards are capable of error-correction as
well. The modem will re-transmit a faulty data block when an error is
detected while receiving.

Page:4

The ITU-T V.42bis can perform data compression at a rate up to four
times, depending on the format of data. That is, the throughput can be
reach as high as 57,600 bits per second when you are on-line at 14,400
bps.

The MNP 5 was popular before V.42bis was born. It can reach a
compression rate of two times, that is around half of what V.42bis can
do.

To enjoy the effectiveness of ECDC, both modems on-line should
exercise the same ECDC standard. You should always set your modem
to V.42bis auto-reliable mode by command \N3, which will
automatically negotiate with the remote modem for an available ECDC
standard.

Controlling the Modem Speaker _____________________________

In the factory, your modem speaker is preset in to medium volume and
turned on when the carrier from the remote modem is detected. You
may issue the commands L and M, with an appropriate parameter
following it, to control the volume, or turn on the speaker.

Page:5

__________ The Modem Commands _________

Prefix, Repeat and Escape Commands ________________________

AT Attention. Precede all command lines except A/ and +++
A/ Re-execute the last command in command buffer
+++ Escape characters, requires guard time before and after

Dial Commands and Dial Modifiers __________________________

D Originate a call
S=n Dial the n

th

stored number

T Touch tone dialing
P Pulse dialing
R Dial in answer mode
W Wait for second dial tone

L Re-Dial the last valid telephone

number

, Pause
! Flash
; Return to command state

Operation Commands______________________________________

A Answer incoming call
B0 CCITT or ITU-T compatibility

B1 Bell protocol only
E0 Disable command echo

E1 Enable echo command

characters

H0 Hang up the connection

(on-hook)

H1 Go off-hook to make a call
I0 Reports product code

I1 Calculates the ROM checksum
I3 Reports firmware version

L0 Low volume
L1 Low volume
L2 Medium volume
L3 High volume

M0 Speaker off at all times
M1 Speaker on until CD detected

M2 Speaker always on
N0 Fixed data rate follow *N

command

N1 Enable adaptive data rate
O0 Return to data-link without

retrain

O1 Return to data-link with retrain
Q0 Modem se nds r e sponse codes

Q1 Do not send response codes
Sr? Display the value in register r

Sr=n Set register r to a value n
V0 Display response codes in digit

form

V1 Display response codes in

words

W0 Disable V.42 response codes,

display DTE speed

W1 Enable V.42 response codes,

Page:6

display DCE speed

W2 Disable V.42 response codes,

display DCE speed

X0 Enable basic response codes

0-4

X1 Do not detect dial tone and

busy signal

X2 Include dial tone detection

response

X3 Include busy detection

response

X4 Enable all response codes
Y0 Do Not send (and ignore)

break signal

Y1 Send break signal for 4

seconds before disconnect

Z0 Reset modem with SCP0
Z1 Reset modem with SCP1

&C0 Turn CD signal to always on
&C1 CD on at remote carrier

detected

&D0 Alone with any of following

&Q0, &Q5, &Q6 then, DTR is
not functional.
Alone with any of following
&Q1, &Q4 then DTR drop
causes the modem hang up,
Auto-answer is not affected.
Alone with any of following
&Q2, &Q3 DTR drop causes
the modem to hang up,
Auto-Answer is inhibited

&D1 Alone with any of following

&Q0, &Q1, &Q4, &Q5, &Q6
DTR drop is interpreted by the

modem as if the asynchronous
escape sequence had been
entered. the modem return to
asynchronous command state
without disconnecting.
Alone with any of following
&Q2, &Q3 DTR drop causes
the modem to hang up.
Auto-Answer is inhibited.

&D2 Alone with any of following

&Q0 through %Q6 then,
DTR drop causes the modem
to hang up Auto-Answer is
inhang.

&D3 Alone with any of following

&Q0, &Q1, &Q4, &Q5, &Q6
DTR drop causes the modem to
perform a softreset as if the z
command were received. The &
Y setting determines which
profile is loaded.
Alone with any of following
&Q2, &Q3 DTR drop causes
the modem to hang up
Auto-Answer is inhibited.

&F0 Restore factory default profile

FDP0 (as ECDC modem)

&F1 Restore factory default profile

FDP1 (as non-ECDC modem)

&G0 Disable guard tone
&G1 Disable guard tone (default for

us models)

&G2 Enable 1800 Hz guard tone
&Ln Leased line dail line operation

&L0 Dial-Up line operation
&G2 Leased line operation

&K0 Disable flow control

Page:7