Synxcom SM19202FP User manual

User’s Manual
For Models
SM19202FP, SM19202FP-K
SM96202FP, SM96202FP-K
Fast Poll Modems
Document Number 520-01014-001 Rev. C

Copyright © 2012 Synxcom, Incorporated.
All Rights Reserved.
Web site: www.synxcom.com
The products and programs described in this User’s Manual are licensed products of Synxcom Inc.
This User’s Manual contains proprietary information protected by copyright, and this User’s Guide and
all accompanying hardware and documentation are copyrighted.
Synxcom Inc. does not warrant that the product will work in all environments and applications, and
makes no warranty and representation, either implied or expressed, with respect to the quality,
performance, merchantability, or fitness for a particular purpose.
Information in this User’s Guide is subject to change without notice and does not represent a
commitment on the part of Synxcom Inc. Synxcom Inc. assumes no responsibility for any
inaccuracies that may be contained in this User’s Manual.
No part of this manual may be reproduced or transmitted in any form or by any means, electronic or
mechanical, including photocopying, recording, or information storage and retrieval systems, for any
purpose other than the purchaser's personal use, without the express written permission of Synxcom
Inc.
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Technical Support is available from 8:00 am to 5:00 pm PST, weekdays except major holidays.
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SM19202FP Fast Poll Modem User’s Manual
520-01014-001 Rev. C
March 15, 2012

iii User’s Manual - SM19202 Fast Poll Modem
Contents
Chapter 1 Introduction ............................................................................................ 6
Features....................................................................................................................7
Applications...............................................................................................................8
Chapter 2 Installation.............................................................................................. 9
Unpacking Your Hardware.........................................................................................9
Additional Items You Need to Complete Your Installation..........................................9
Hardware Overview.................................................................................................10
Front View...............................................................................................................10
Back View................................................................................................................10
Rack-Mount View.....................................................................................................11
Installation Summary...............................................................................................11
Configuring the Stand-alone Modem........................................................................12
Setting the DIP Switches .........................................................................................14
S1-1, S1-2, S1-3 −Modem Data Rate................................................................15
S1-4 −Async Character (Fast-Poll Mode Only)..................................................16
S1-5 −Auto RTS................................................................................................16
S1-6 −Transmit Carrier Control (For SM19202FP-K only)...............................16
S1-7 −2-/4-Wire Leased Line Operation............................................................17
S1-8 −Transmitter Impedance...........................................................................17
S1-9 −Remote Loopback Enable ......................................................................18
S1-10 −Reserved (Test Only)............................................................................18
S2-1 through S2-3 −Transmit Level...................................................................18
S2-4 −Receiver Dynamic Range.......................................................................19
S2-5 and S2-6 −Cable Equalizer (Fast-Poll Mode Only)....................................19
S2-7 −Anti-streaming ........................................................................................19
S2-8 −RTS-CTS Delay (Bell 202 Mode Only)....................................................19
S2- 9−Forced RTS ON (Constant RTS) ...........................................................20
S2- 10−Re-Train Request Enabled.........................................................................20
S3- 1 and S3-2−RS-232 or RS-485 Interface Select..............................................20
S3-3 RS-485 Receiver Termination........................................................................21
S3-4- Not Used..................................................................................................21
S-3-5 Leased Line Receiver Termination...........................................................21
S3-6- Common Signal Ground and Chassis Ground .........................................21
Configuring the Jumper Blocks................................................................................21
For Stand-alone Units........................................................................................21
For Rack-Mount Plug-in Modules.......................................................................21

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iv User’s Manual - SM19202 Fast Poll Modem
Connecting to a Transmission Line..........................................................................22
Connecting to a Voltage Source ..............................................................................23
Connecting to an RS-232 Device.............................................................................24
Connecting to an RS-485 Device.............................................................................24
LEDs........................................................................................................................26
Loopback Control Switch.........................................................................................26
Appendix A Troubleshooting................................................................................ 28
Problem Solving ......................................................................................................28
Appendix B Specifications ................................................................................... 29
General Specifications.............................................................................................29
Mechanical Specifications........................................................................................30
Interface Connector Pin Assignments......................................................................30
RS-232 (DTE) Interface...........................................................................................31
RS-485 (DTE) Interface...........................................................................................31
Environmental Specifications...................................................................................31
Appendix C Limited Product Warranty................................................................ 32
Appendix D RMA Procedure................................................................................. 33

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v User’s Manual - SM19202 Fast Poll Modem
Figures
Figure 1-1. Point-to-Point Network Using the SM19202FP Modem.......................................8
Figure 1-2. Multipoint Polling Network Using the SM19202FP Modem..................................8
Figure 2-1. Front View of the SM19202FP Modem..............................................................10
Figure 2-2. Back View of SM19202FP Modem....................................................................10
Figure 2-3. Rack-Mount Module for the SM19202FP-RM Modem Board.............................11
Figure 2-4. SM19202 Fast-Poll Stand-alone Modem Switches............................................13
Figure 2-5. SM19202 Fast-Poll Rack-mount Modem Board.................................................14
Figure 2-6. SM19202FP Modem Transmission Line Interface.............................................22
Figure 2-7. Pin Locations on the Modem’s RJ-11C Jack.....................................................24
Figure 2-8. Loopback Diagnostic Modes .............................................................................27
Figure 2-9. Back-to-Back Connection to a Second Modem .................................................30
Tables
Table 2-1. Modem Switch Settings......................................................................................14
Table 2-2. Modem Operating Speed ...................................................................................16
Table 2-3. Transmit Levels..................................................................................................18
Table 2-4. Transmission Line Connector Pin Assignments..................................................22
Table 2-5. RJ-11C Modular Jack Pin Assignments..............................................................24
Table 2-6. Modem LEDs .....................................................................................................26
Table A-1 Problem Solving.................................................................................................28
Table B-1. Leased Line Terminal Block Pin Assignments....................................................30
Table B-2. RS-232 (DTE) Interface .....................................................................................31
Table B-3. RS-485 (DTE) Interface .....................................................................................31

6 User’s Manual - SM19202 Fast Poll Modem
Chapter 1
Introduction
Thank you for purchasing Synxcom’s SM19202FP fast poll modem, the finest industrial-
grade fast-poll modem available.
The Synxcom modem is a 19200/9600/4800/2400/1200 bps modem designed for 4-wire,
full-duplex or 2-wire, half-duplex operation over a voice-band leased line or private line. The
modem is designed utilizing the latest digital-signal processing (DSP) technology to achieve
high performance. The modem employs efficient modulation and encoding scheme to
achieve fast modem training time. The modem is also backward compatible with Bell 202
and ITU-T V.23 modems.
The SM19202FP is the most technologically advanced modem on the market. Boasting a
fast DSP processor and automatic adaptive equalizer, the SM19202FP modem is ideally
suited for multi-point communication systems that require fast response time, short training
time, and low throughput delay.
This User’s Guide describes the SM19202FP (AC-powered) and SM19202FP-DC (DC-
powered) stand-alone modems, as well as the rack-mount SM19202FP-RM plug-in module
for the Motorola/UDS RM16M. This manual is designed to get your modem “up and running”
as quickly as possible. It contains all the information you need to configure and install your
modem. It also contains troubleshooting information in the unlikely event you encounter a
problem with your modem.

Introduction
7 User’s Manual - SM19202 Fast Poll Modem
Features
The SM19202FP modem is specifically designed for harsh environments typically
associated in utility substations and industrial facilities. Though functionally similar to
commercial modems, the SM19202FP provides the following unique features that make it
well suited for utility and industrial applications.
Packaged in a rugged, compact enclosure for industrial applications.
Leased-line interface protected with heavy-duty surge protection devices.
Built-in hardware watchdog timer for software lock-up prevention without requiring
human intervention, making it ideal for unmanned locations.
Works within an extended temperature range of -40ºC to +85ºC.
Designed with coupling transformers for high-voltage isolation and common mode
noise rejection in industrial and commercial environments.
Operate over voice-band conditioned or unconditioned leased-line and pilot wires.
Accepts power from a wide range of AC and DC power supplies:
– SM19202FP: 90 to 265 VAC or 100 to 400 VDC
– SM19202FP-DC: 10 to 60 VDC
– SM19202FP-RM: Plug-in module for the Motorola/UDS RM16M modem nest
Standard industrial connectors for data, analog, and power interfaces allow reliable
interconnection to other industrial equipment.
Asynchronous data rates (selectable) of 19200, 9600, 4800, 2400, and 0-1800
bps.
Easily accessible DIP switches for user configuration and option selection.
DB9-F connector for RS-232/V.24 interface, and RJ-11 for RS-485.
Local analog, local digital, and remote digital loopback diagnostics.

Introduction
8 User’s Manual - SM19202 Fast Poll Modem
Applications
The SM19202FP modem is designed for point-to-point and multipoint data communications.
Figure 1-1 shows a typical point-to-point configuration using the SM19202FP modem and
Figure 1-2 shows a typical multipoint configuration using the SM19202FP modem.
Workstation Modem Modem
Remote Terminal
Figure 1-1. Point-to-Point Network Using the SM19202FP Modem
Workstation Modem
Modem
Modem
Modem Modem
Modem
Remote Terminal
Remote Terminal
Figure 1-2. Multipoint Polling Network Using the SM19202FP Modem
There are a number of factors that can affect the modem’s operation and performance.
These include:
Modem speed (i.e. bit error rate, transmission line distance)
2-wire or 4-wire configuration
Transmission line characteristics, noise, and line impairments
Network configuration (point-to-point or multipoint)

9 User’s Manual - SM19202 Fast Poll Modem
Chapter 2
Installation
This chapter describes how to configure and install the modem to maximize the performance
and to match with your Data Terminal Equipment (DTE) or Remote Terminal Unit (RTU).
Unpacking Your Hardware
Your package should include:
At least one of the following SM19202FP modems:
– Model SM19202FP for 90 to 265 VAC
– Model SM19202FP-DC for 10 to 60 VDC
– Model SM19202FP-RM for RM16M plug-in module
A switching power supply module for 90-265VAC input (model SM19202FP only)
A leased-line cable with optional earth ground conductor (for stand-alone units
only)
A DC power cable (model SM19202FP-DC modem only)
This User’s Manual or CD-ROM
If your package contents are damaged or missing, contact your place of purchase.
Additional Items You Need to Complete Your Installation
To complete your installation and operate your modem, you need these additional items:
Two- or four-wire transmission line or leased line
A DB-9 data cable for your RS-232 interface Data Terminal Equipment (DTE) port,
or a RJ-11C data cable for your RS-485 DTE.
Power supply that provides either:
– 90 to 265 Volts AC, 50 to 60 Hz, single phase or 100 to 400 VDC (if you have
the model SM19202FP modem), or
– 10 to 60 Volts DC (if you have the model SM19202FP-DC modem)
– For the SM19202FP-RM, consult the documentation for your Motorola/UDS
RM16M

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10 User’s Manual - SM19202 Fast Poll Modem
Hardware Overview
Front View
Figure 2-1 shows the front view of the SM19202FP stand-alone modem. Starting from the
left side, this view shows:
A set of eight LEDs for modem interface status (see Table 2-6 on page 26)
A loopback control push-button switch (see Loopback Control Switch on page 26)
Figure 2-1. Front View of the SM19202FP Modem
Back View
Figure 2-2 shows the back view of the SM19202FP stand-alone modem. Starting from the
left side, this view shows:
A 4-wire/2-wire configuration block labeled LEASED LINE
An RJ-11 modular jack labeled RS-485 for connecting the modem to an RS-485
RTU
A female, 9-pin RS-232 connector labeled RS-232 for connecting the modem to a
standard DTE (RTU)
A power connector labeled 10-48V DC
Figure 2-2. Back View of SM19202FP Modem

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11 User’s Manual - SM19202 Fast Poll Modem
Rack-Mount View
Figure 2-3 shows the rack-mount plug-in module.
Figure 2-3. Rack-Mount Module for the SM19202FP-RM Modem Board
Installation Summary
This section describes the steps for installing the modem.
NOTE:
It is important to follow the steps below to configure the modem’s DIP
switches to match your DTE/RTU interface requirement and the transmission
line characteristics. If you are not certain about your system’s parameters or
the leased-line configuration, please contact your network administrator for
assistance.
1. Configure the modem using the DIP switches and jumpers. See pages 14 and 20.
2. Connect to a transmission line. See page 22.
3. Connect to a voltage source. See page 23.
4. Connect a DTE device. See page 24.

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12 User’s Manual - SM19202 Fast Poll Modem
Configuring the Stand-alone Modem
You configure the modem using the three sets of DIP switches located at the bottom of the
modem box S1 and S2, and S3.
Configuration DIP switches S1 and S2 for the stand-alone and rack-mount modems are
identical. Their descriptions in this user’s manual apply to both modem versions.
Configuration jumper JP1 for the rack-mount modem card is used to select receiver
termination impedance.
It is important to follow the steps described below, in the order shown, to ensure that you
configure your modem properly using the modem DIP switches:
1. Use DIP switch 1 (S1) to configure the modem for your host DTE interface and
network topology. Using S1, you select the modem’s operating speed to match
you host computer or RTU devices, and other DTE specific operating
parameters.
2. Use DIP switch 2 (S2) to select the modem’s transmitter output level and receiver
dynamic range specific leased line conditions. The S2 settings apply for both
high-speed fast-poll (QAM) and low-speed (FSK) modes.
3. After you change the DIP switch settings, recycle power to the modem to have
the settings take effect.
NOTE:
The DIP switch settings may not take effect until you recycle power to the
modem.
To access the configuration DIP switches on the stand-alone modem:
1. Ground yourself to discharge any ESD, which might cause damage to the
sensitive devices on the modem board.
2. Due to re-designing of the modem’s main assembly circuit board and the chassis,
you do not need to open the enclosure to get access to the DIP switches . Place
the modem on a flat surface with the bottom up. The locations of the DIP
switches for the stand-alone modem are shown in Figure 2-4 on the next page.
To set the configuration for the modem, use a sharp pin or small screw driver to
slide the switch lever to the ON or OFF positions as shown in Table 2-1.
For DIP switches and jumpers on the rack-mount plug-in module, see Figure 2-5.
***IMPORTANT***
Carefully check the DIP switches for the ON (close) or OFF (open) positions
according to your RTU interface specifications and to match the data rate and
other control inputs to the modem.

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13 User’s Manual - SM19202 Fast Poll Modem
Figure 2-4. SM19202 Fast-Poll Stand-alone Modem Switches

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14 User’s Manual - SM19202 Fast Poll Modem
J1
U19
T2
T1
U15
U5
GT2 GT1
S3
Y2
U18
U17
D11 D10
Y1
F1
F2
F3
F4
U15
U1
Data Rate 1 Data Rate 2 Data Rate 3 CharLength Auto RTS Tx Carrier 4W/2W Tx Impedance RDLBDisable Factoryonly TxLevel1
TxLevel2
TxLevel3
RcvRange
TxEqualizer
RxEqualizer
Anti-Stream
RTS-CTSDelay
Option1
Option2
D2 D1D3D4D5D6D7D8D9
U3 U8
U10
U6
U12
GT4 GT3
U2 U4
D27 D25
E1
E2
E3
J2
12
13 14
U7 U9
U22
U14
11 10 10
S1 S2
U21
31
JP1
600 ohmHigh-Z
Configuration Jumper
for Receiver Termination
Configuration DIP Switches
Figure 2-5. SM19202 Fast-Poll Rack-mount Modem Board
Setting the DIP Switches
S1, S2 and S3 are miniature switches used to configure all the options and features of the
modem. Table 2-1 shows the setting of the switches.
NOTE:
Switches S1 to S3 are slide switches. To configure the switches, use a small
sharp pin or small screw driver to push the handle to turn ON or to turn OFF
each switch. Never leave any switch in half way ON or OFF. When the switch
is slide to the ON position, it is referring to as CLOSE condition. When the
switch is in the OFF position, it is in the OPEN state.
Table 2-1. Modem Switch Settings
DIP Switches Switch Settings
ON OFF (Default)
DIP Switch S1
S1-1 to S1-3: Modem Data Rate
19200: SW1=OFF, SW2=OFF, SW3=OFF
9600: SW1=ON, SW2=OFF, SW3=OFF
4800: SW1=ON, SW2= ON, SW3=OFF
2400: SW1=OFF, SW2=ON, SW3=OFF
Bell 202T: SW1=OFF, SW2= OFF, SW3=ON
V.23: SW1=ON, SW2=ON, SW3=ON
S1-4: DTE Async Character 11 bit 10 bit

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15 User’s Manual - SM19202 Fast Poll Modem
DIP Switches Switch Settings
ON OFF (Default)
S1-5: Auto RTS Enabled Disabled
S1-6: Transmit Carrier Control
(SM19202FP-K only) Radio Push-to-Talk option Normal Leased Line
S1-7: 2- or 4-wire leased line 2-wire half duplex 4-wire full duplex
S1-8: Transmitter Impedance Controlled by RTS 600 ohms
S1-9: Remote Digital Loopback Enabled Disabled
S1-10: Test Only (Reserved) Factory Test only Normal Operation
DIP Switch S2
S2-1 to S2-3: Transmit Output Level From -14 to 0 dBm (see Table 2-5)
S2-4: Modem Receive Dynamic Range -10 to -43dBm 0 to -30dBm
S2-5: TX Cable Equalizer Enabled Disabled
S2-6: RX Cable Equalizer Enabled Disabled
S2-7: Anti-streaming Active Inactive
S2-8: RTS-CTS Delay (Bell 202T only) 33 msec 8 msec
S2-9: Forced RTS ON Force RTS & Carrier to ON Controlled by RTS signal
S2-10: Re-Train Enabled (19200 bps only) Enabled Disabled
DIP Switch S3
S3-1: RS-232 Interface operation Both S3-1 and S3-2 are set to OFF
S3-2: RS-485, 4-wire interface
2-wire interface S3-1 = ON, S3-2 = OFF S3-1 = OFF, S3-2 = ON
S3-3: RS-485, Receiver Termination High Impedance 120 Ohms
S3-4: Not Used
S3-5: Receiver Termination 600 Ohms (Default) High Impedance
S3-6: Signal Ground and Chassis Ground Connected Together Open
S1-1, S1-2, S1-3 −
−−
−Modem Data Rate
S1-1, S1-2, S1-3: Select the modem speed per Table 2-2

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16 User’s Manual - SM19202 Fast Poll Modem
Table 2-2. Modem Operating Speed
To Select… Set Switch S1-1 to… Set Switch S1-2 to… Set Switch S1-3 to…
19,200 bps (Note) OFF OFF OFF
9600 bps ON OFF OFF
4800 bps ON ON OFF
2400 bps OFF ON OFF
Bell 202T OFF OFF ON
V.23/1200 ON ON ON
For modem speeds of 2400 bps or higher, the modem uses QAM modulation automatically.
When the modem is operating at 1200 bps either in Bell202T or ITU-V.23 mode, the modem
uses FSK modulation.
Note: Leased lines with a relatively flat 300-3400Hz bandwidth is required to support
19,200 bps operation.
S1-4 −
−−
−Async Character (Fast-Poll Mode Only)
S1-4 ON = 11 bits
S1-4 OFF = 10 bits (default)
Switch S1-4 selects whether the async character is 10 or 11 bits long.
10 bits character: 1 start, 1 stop bit, 7 data + 1 parity(&-E-1), or 8 data with no parity(8-N-1).
11 bits character: 1 start, 1 stop bit, 8 data + 1 parity (8-E-1)
This switch setting is ignored when the modem set at 1200 bps or less (FSK modulation).
S1-5 −
−−
−Auto RTS
S1-5 ON = Enable Auto RTS
S1-5 OFF = Disable Auto RTS (default)
For data terminals that do not provide hardware Request To Send (RTS), i.e. only provide
TXD, RXD, SG connections, set the modem’s switch S1-5 to ON to enable auto RTS mode.
In this mode, the modem does not require RTS input from the DTE or RTU. If TXD is
detected at the modem, the modem turns on its internal RTS and carrier signals at the
transmitter. After training completes, the TXD is transmitted to the remote modem. The
transmitter turns itself off if no TXD is detected after some length of idle time (approx 2
characters).
S1-6 −
−−
−Transmit Carrier Control (For SM19202FP-K only)
S1-6 ON = Enable transmit carrier control for radio push-to-talk

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17 User’s Manual - SM19202 Fast Poll Modem
S1-6 OFF = Normal Leased Line operation (default)
When DIP switch SW1-6 is ON, the modem will activate its Push-To-Talk feature. The
main theory of operation of this feature is for the modem to turn on the radio as soon as
RTS is asserted by the RTU to the SM19202FP-K modem. The modem will use the
delayed Clear-To-Send (CTS) as the indicator to the RTU to signal the start of sending data
to the host end. When the modem turns on the radio by way of a TTL logic low signal (Key-
on), the modem will wait for 30 msec before start sending any analog signal to the radio
and the master modem end. This timing is critical and is required by the radio and the
modem to ensure the training pattern of the modem is fully transmitted without distortion.
For RTUs that only provide the 3-wire RS-232 interface, or using the RS-485 interface, the
modem will not receive the RTS signal for the key-on function. As such, the modem must
be configured to enable the “Auto-RTS” option (SW1-5 to ON). With this option, the
modem will generate its internal RTS when data is detected from the RTU and turn on the
“Push-To-Talk” signal to the radio.
Note: Please refer to switch setting S2-9; forced RTS ON for other applications.
S1-7 −
−−
−2-/4-Wire Leased Line Operation
S1-7 ON = 2-Wire, Half-Duplex Mode
S1-7 OFF = 4-Wire, Full-Duplex Mode (default)
Switch S1-7 configures the modem for either 4-wire full-duplex or 2-wire half-duplex leased
line operation.
S1-8 −
−−
−Transmitter Impedance
S1-8 ON = Transmitter termination is controlled by RTS
S1-8 OFF = Transmitter always terminated with 600 Ω(default)
Switch S1-8 is used for multi-point configuration networks. When multiple modems are
connected on the same metallic circuit:
The transmitter termination should be of high impedance if the modem is not
transmitting in order not to put a load on the transmission line.
The transmitter is only terminated with 600 ohms when RTS is asserted.
This configuration should be used for all slave modems to prevent the transmitting modem
from being unnecessarily burdened. To select this configuration, set switch S1-8 ON for the
slave modems such that the slave modem is in high impedance when not transmitting.

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18 User’s Manual - SM19202 Fast Poll Modem
If you use the modem with transmission lines that are transformer-coupled or with an
impedance-isolated network (such as a transformer bridge), set switch S1-8 OFF for proper
operation.
S1-9 −
−−
−Remote Loopback Enable
S1-9 ON = Loopback enabled
S1-9 OFF = Loopback disabled (default)
During instances of channel noise, the modem may mistake a received preamble as a
request to go into remote digital loopback. Setting switch S1-9 to OFF prevents the modem
from participating in a remote digital loopback with another modem. Switch S1-9 does not
prevent the modem from sending a remote digital loopback request to a remote modem.
S1-10 −
−−
−Reserved (Test Only)
S1-10 = must be OFF for normal modem opertation
Switch S1-10 must be in the OFF position for normal operation. It is reserved for factory
testing only.
S2-1 through S2-3 −
−−
−Transmit Level
Switches S2-1 through S2-3 are used to adjust the modem’s transmit level. Table 2-5 shows
the transmit levels you can select using these switches.
Table 2-3. Transmit Levels
Transmit Level S2-1 through S2-3 Switch Settings
S2-1 S2-2 S2-3
0 dBm OFF OFF OFF
−2 dBm OFF OFF ON
−4 dBm OFF ON OFF
−6 dBm OFF ON ON
−8 dBm ON OFF OFF
−10 dBm ON OFF ON
−12 dBm ON ON OFF
-14 dBm ON ON ON

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19 User’s Manual - SM19202 Fast Poll Modem
S2-4 −
−−
−Receiver Dynamic Range
S2-4 ON = −10 to −43 dBm
S2-4 OFF = 0 to −30 dBm (default)
For short distances or to select a strong receive signal, set S2-4 to OFF. For a long-distance
cable or low receive signal level, set S2-4 to ON (−43 dBm).
S2-5 and S2-6 −
−−
−Cable Equalizer (Fast-Poll Mode Only)
S2-5 ON = Enable TX Cable Equalizer
S2-5 OFF = Disable TX Cable Equalizer (default)
S2-6 ON = Enable RX Cable Equalizer
S2-6 OFF = Disable RX Cable Equalizer (default)
If you use the SM19202FP as a limited-distance modem over pilot wire or unloaded cables,
you may need to improve or extend the modem’s polling performance on long transmission
lines by using the modem’s internal fixed Compromise Cable Equalizer when polling on long
metallic circuits when the cable exceeds 4 to 5 miles long. The cable equalizer is active only
when the modem is in QAM fast-poll mode (2400 bps or higher).
S2-7 −
−−
−Anti-streaming
S2-7 ON = Anti-streaming is active
S2-7 OFF = Anti-stream is inactive (default)
Typically, anti-streaming is used in multi-point applications to prevent a malfunctioning slave
data terminal or RTU from occupying the line indefinitely. When anti-streaming is active, the
modem can transmit data for a maximum of 27 seconds before the transmitter turns off
automatically. The modem then looks for an ON-to-OFF RTS transition before proceeding
with normal operation. Anti-streaming can be selected in either high-speed or low-speed
mode.
S2-8 −
−−
−RTS-CTS Delay (Bell 202 Mode Only)
S2-8 ON = 33.0 ms delay
S2-8 OFF = 8.0 ms delay (default)
Switches S2-8 determines the duration of the RTS-CTS delay in Bell 202 mode.
For V.23 mode, the RTS-CTS delay is fixed at 33 ms.

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20 User’s Manual - SM19202 Fast Poll Modem
S2- 9−
−−
−Forced RTS ON (Constant RTS)
S2-9 ON = Force the modem’s internal RTS to on. It also force the modem to turn
on CTS and the transmit carrier.
S2-9 OFF = Internal RTS is controlled by the RTU (default)
Switch 2-9 will force the modem to turn on its internal RTS, CTS and transmit carrier
continuously, allowing the RTU and DTE to operate with the modem without supplying RTS
signal. This is primary used by DTE’s or RTU’s that support only TD, RD and SG signals.
Forced RTS on option is typically used for point-to-point connections between two RTUs or
modems. For multi-point applications, the salve modems should not use this option.
S2- 10−
−−
−Re-Train Request Enabled
When the SM19202FP modems are operating in high-speed polling modes, the modem’s
receivers require a special training pattern from the remote transmit modem to synchronize
the receive timing before data can be received. The SM19202FP will only send out a training
pattern when the transmit modem’s RTS is raised from the OFF to ON state (i.e. Switched
Carrier mode). However, if the modems are configured in Constant Carrier mode, or the
RTS is ON continuously by the DIP switches, no training pattern will be sent from the
transmit modems. When in configurations where constant carrier is received at the
modem’s receiver, there is a possibility that the modem might lose synchronization due to
transmission line interferences such as line hits, line drop-outs, or power outage conditions.
In order to regain synchronization at the receiver, the SM19202FP modem implements a re-
train algorithm which allows the receiving modem to send out a re-train request to the
remote modem for re-train and re-gain synchronization. This option is most useful for the
modem to operate at 19200 bps and constant carrier or constant RTS modes.
S2-10 ON = Re-Train Request is Enabled (for 19,200 bps only)
S2-10 OFF = Re-Train Request is Disabled (default)
S3- 1 and S3-2−
−−
−RS-232 or RS-485 Interface Select
The SM19202FP standalone modem support either RS-232/V24 or RS-485 4-wire or RS-
485 2-wire operation. To select the interface standards to match you RTU, configure S3-1
and S3-2 as following:
•RS-232/V.24: S3-1 = OFF, S3-2 = OFF
•RS-485, 4-wire: S3-1 = ON, S3-2 = OFF
•RS-485, 2-wire: S3-1 = OFF, S3-2 = ON