Digicom SNM15 User manual

SNM15
OPERATION MANUAL
SNM15 rev.1.0 del 07/91 COD.7D0548

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without the prior written permission of the publishers.
The contents of this booklet may be modified without
prior permission.
Every possible care has been taken in testing and
putting together all the documentation contained in
this booklet, however DIGICOM can not take any
responsability brought by the use of this booklet.

INDEX
INTRODUCTION 1.1
OVERALL FEATURES 1.1
Mechanical Dimensions 1.1
Environmental Conditions 1.2
Mains Power Supply 1.2
Analog Interface 1.5
Control and Warning Devices 1.7
FUNCTIONAL FEATURES 2.1
Operational Modes 2.1
Error correction and data compression 2.2
MNP 2.3
CCITT V.42 and V.42bis 2.6
INSTALLATION 3.1
introduction 3.1
Connection to the DTE Data Terminal 3.1
Connecting to the Telephone Line and Telephone 3.1
Operational Test 3.3
USE OF THE MODEM 4.1
introduction 4.1
Control and worning devices 4.1
Control Devices on the Front Panel 4.1
Warning Devices 4.3
AT commands 4.4
Command Buffer 4.5
Auto-Baud and Auto-Parity Detection 4.6
Data length 4.6
AT COMMAND SET DESCRIPTION 5.1
LIST OF THE MESSAGES IN SHORT AND EXTENDED FORMS 5.7
Default configuration 5.24

V.25 bis 6.1
Introduction 6.1
Duties of the DTE 6.1
Definitions and Operational Modes 6.2
ASYNCHRONOUS V.25BIS COMMANDS 6.8
Separators 6.12
ASINCHRONOUS V.25BIS INDICATIONS 6.13
SYNCHRONOUS V.25BIS COMMANDS 6.20
SYNCHRONOUS V.25BIS INDICATIONS 6.21
Line procedures 6.22
Default configuration of the commands from AT to V.25bis 6.22
Default configuration of S-Registers from AT to V.25bis 6.23
DIAGNOSTICS 7.1
Introduction 7.1
Enabling Remote Loop 2 7.1
Disabling Remote Loop 2 7.2
Enabling Loop 3 7.2
Disabling Loop 3 7.3
Resetting the Hardware 7.3
USE OF THE S-REGISTERS 8.1
introduction 8.1
Content of the Main Registers 8.1
Default configuration of the register 8.6
TYPICAL APPLICATIONS 9.1
introduction 9.1
Asynchronous connection without auto answer feature 9.1
Connection in V.22 and MNP 9.2
Synchronous connection 9.2
Appendix A
Dip-Switches Setting A.1
Terminal Emulation Program A.4

1.1
SNM15 Introduction
Digicom SpA
INTRODUCTION
OVERALL FEATURES
The SNM 15 modem is externally designed with a metal frame.
The cards are pulled out by pressing the lever located beneath the
front panel.
On the front panel there are indicating lights for the main interface
circuits, the operational condition of the modem and the operation
and test enabling switches.
On the rear panel there are the power supply cord, the protection
fuses and the mains switch. There are also the line connector and
the two ISO 2110 type female connectors to terminate the
DTE(s).
The modem is supplied together with the present manual with a
cable for the connection to the telephone plug.
Mechanical Dimensions
Width : 190 mm.
Height : 44 mm.
Depth : 266 mm.
Weight : 2 Kg.

1.2
SNM15 Introduction
Digicom SpA
Environmental Conditions
Operational temperature : from 0°C to +50°C
Storage temperature : from -20°C to +80°C
Relative moisture : from 5% to 92% non condensing
Mains Power Supply
Power supply voltage : 220 Vac. (-15% : +10%) frequency
47 : 63 Hz.
Consumption : 3 VA
Digital Interface
The modem is equipped with two data interfaces: MAIN PORT
and COMMAND PORT. The former can be used indifferently for
programming the modem and transmitting data to a remote
modem, the latter can only be used to program the modem.
Communication procedure : asynchronous Start/Stop serial
Character format : see table:
1 start bit 7 data bits even/odd 1 stop bit
1 start bit 7 data bits mark/space 1 stop bit
1 start bit 7 data bits no parity 2 stop bits
1 start bit 8 data bits no parity 1 stop bit
MAIN PORT : The connector marked by this
abbreviation is the main port of the
modem. By using this connector,
the initial functions of
programming and enabling

1.3
SNM15 Introduction
Digicom SpA
connection and the real primary
function of transmitting data are
performed. The latter function can
beperformedineithersynchronous
or asynchronous mode.
COMMAND PORT : This port can only be used to send
the commands to the modem. The
criteria: CTS, DSR, DCD, when
the port is active, are forced into a
working condition so as to allow
data to be transferred from the
DTE to the DCE and vice-versa.
Operational mode : In order to program and enable the
connection, the format is start-
stop asynchronous, whereas data
can be transmitted in either
asynchronous or synchronous
format.
Characters Code : the ASCII code is used for
programming, while there are no
limitations once it has been
connected, the BREAK signal is
also transferred according to the
CCITT V.22 standard.
Type of interface : In compliance with the CCITT
V.24/V.28 or EIA RS.232C
specifications, the 25 contact
female connectors conform to the
ISO 2110 standards.

1.4
SNM15 Introduction
Digicom SpA
Cont. Circuit Direction Mnem. Description
Conn. V.24 RS 232 DTE-SNM15Abbrev.
2 103 BA ————> TD Transmit data
3 104 BB <———— RD Receive data
4 105 CA ————> RTS Request to transmit
5 106 CB <————> CTS Clear to transmit
6 107 CC <———— DSR Modem ready
7 102 AB <————> SG Signal ground
8 109 CF <———— DCD Data carrier detect
9 - - <———— +12 V test voltage
10 - - <———— -12 V test voltage
11 - -
12 - -
13 - -
14 - -
15 114 DB <———— TC Internal transmission
clock
16 - -
17 115 DD <———— RC Reception clock
18 141 CN ————> L3 Request for loop 3
19 CCONF pin (see *M
command)
20 108.2 CD ————> DTR Data terminal ready
21 140 CF ————> RDL Request for remote Loop
22 125 CE <———— RI Ring Indication
23 112 CI <———— Speed section for DCE
(Note 1)
24 113 DA ————> ETC External transmission
clock
25 142 - <———— TI Active loop
Interface circuits

1.5
SNM15 Introduction
Digicom SpA
Note: contacts 11, 12, 13, 14 and 16 have been left free.
Transmitted data clock : in synchronous operation, the
modem needs a clock for data
transmission. This may be
generated by the modem (internal
clock) and supplied to the DTE via
the interface circuit C114. The
modem also accepts an external
timer (external clock) supplied on
circuit C113 of the interface,
provided that it has the tolerance
levels envisaged by the CCITT.
Received Data Clock : in synchronous mode, the modem
deals with timing the received data
on circuit C115.
Analog Interface
Transmitting support : 2 balanced wires per switched line
(private PABX exchange or public
PSTN network).
Transmission level : from -1 to -16 dBm that can be
adjusted by 1 dbm step.
Data carrier : V.21 300 bps FSK
V.22 1200 bps DPSK
V.22bis 2400 bps QAM

1.6
SNM15 Introduction
Digicom SpA
Threshold of the receiver : definitely OFF with a carrier level
(DCD) lower than -48 dBm;
definitely ON with a level at -43
dBm.
Call detector : frequency from 25 Hz to 50 Hz;
sensitivity 20 Veff or higher;
insensitivity 15 Veff or lower.
C125 (RI) delay : 500 ms ±100 ms compared to the
initial call voltage.
Answer tone : 2100 Hz ±1 Hz of the duration of
3.3 sec ±1 ms.
Automatic disconnection : within 30 seconds per failure to
synchronize with the
corresponding modem
(selectable); once connected, due
to loss of carrier, 700 ms
(selectable).
Type of call : can be selected to emit pulses
(decadic) or multi-frequency
(DTMF).
Recurrence frequency : 10 ±1 pulse/sec.
Open/close ratio : 40/60 ms.
Pause between bits : 800 ms ±50 ms.