Patton electronics 2500 Series User manual

USER
MANUAL
MODEL 2500 Series
Models 2500, 2510, 2520
All-Rate CSU/DSU
SALES OFFICE
[phone]
TECHNICAL SUPPORT
[phone]
Part# 07M2500-C
Doc# 099021UC
Revised 3/13/96

TABLE OF CONTENTS
Section Page
1.0 General Information...............................................................2
1.1 Warranty Statement
1.2 Radio and TV Interference
1.3 FCC Information
1.4 Service Information
2.0 Product Overview ..................................................................4
2.1 Product Features
2.2 General Product Description
2.3 Supported Applications
3.0 Installation .............................................................................6
3.1 DTE Interface Connections
3.2 Network Interface Connections
3.3 Control Port Interface
3.4 Power
4.0 Configuration .........................................................................8
4.1 Configuration Using Hardware Switches
4.2 Configuration Using Software Switches
5.0 Operation.............................................................................23
5.1 LED Descriptions
5.2 Status Displays
5.3 Loopback Test Modes
5.4 The V.52 BER Test Pattern Generator
5.5 Switched 56 Dialing Commands (Models 2510 & 2520)
Appendix A - Specifications
Appendix B - Cable Recommendations
Appendix C - Factory Replacement Parts and Accessories
Appendix D - Interface Pin Assignments
Appendix E - Transmitter Clock Source During Test Loops
1
1.0 GENERAL INFORMATION
Thank you for your purchase of this Patton Electronics product.
This product has been thoroughly inspected and tested and is
warranted for One Year parts and labor. If any questions or problems
arise during installation or use of this product, please do not hesitate to
contact Patton Electronics Technical Support at [phone].
1.1 WARRANTY STATEMENT
Patton Electronics warrants all Model 2500 Series components to
be free from defects, and will—at our option—repair or replace the
product should it fail within one year from the first date of shipment.This
warranty is limited to defects in workmanship or materials, and does not
cover customer damage, abuse, or unauthorized modification. This
product contains no serviceable parts; therefore the user shall not
attempt to modify the unit in any way. If this product fails or does not
perform as warranted, your sole recourse shall be repair or replacement
as described above. Under no condition shall Patton Electronics be
liable for any damages incurred by the use of this product. These
damages include, but are not limited to, the following: lost profits, lost
savings and incidental or consequential damages arising from the use
of or inability to use this product. Patton Electronics specifically
disclaims all other warranties, expressed or implied, and the installation
or use of this product shall be deemed an acceptance of these terms by
the user.
1.2 RADIO AND TV INTERFERENCE
The Model 2500 Series generates and uses radio frequency
energy, and if not installed and used properly—that is, in strict
accordance with the manufacturer's instructions—may cause
interference to radio and television reception. The Model 2500 Series
has been tested and found to comply with the limits for a Class A
computing device in accordance with the specifications in Subpart J of
Part 15 of FCC rules, which are designed to provide reasonable
protection from such interference in a commercial installation.
However, there is no guarantee that interference will not occur in a
particular installation. If the Model 2500 Series does cause interference
to radio or television reception, which can be determined by
disconnecting the cables, the user is encouraged to try to correct the
interference by one or more of the following measures: moving the
computing equipment away from the receiver, re-orienting the receiving
antenna, and/or plugging the receiving equipment into a different AC
outlet (such that the computing equipment and receiver are on different
branches).
2

2.0 PRODUCT OVERVIEW
This section provides an overview of the Model 2500 Series,
including features, general description, and a breakdown of model
numbers by application.
2.1 PRODUCT FEATURES
• Operates over 4-wire dedicated digital lines
• Supports rates of 56 kbps and 64 kbps and all sub rates
• Supports Switched 56 dialing
• Provides both RS-232 and V.35 interfaces
• Features V.52 and V.54 compliant tests
• Nine easy-to-read LED indicators to monitor data signals
• Internal, external or received loopback clocking
• AT&T 62310 compliant
• Can be used as a high speed modem for private twisted pair
• Available in rack card and clusterbox versions
• Made in the USA
2.2 GENERAL PRODUCT DESCRIPTION
The Model 2500 Series CSU/DSUs operate either synchronously
or asynchronously over 4-wire circuits up to 64 kbps. Rate conversion
allows operation with a variety of DTE devices. Diagnostics include
V.54 and V.52 loopback tests, as well as CSU loops. Configuration is
accomplished by either externally accessible DIP switches or RS-232
software switches (user provides terminal). Nine easy-to-read front
panel LED indicators monitor data and control signals. The rear panel
presents both RS-232/V.24 and V.35 DTE connections.
The Model 2500 Series is AT&T compliant and supports DDS,
Switched 56, Clear Channel 64 and other digital services available from
major service providers including AT&T, Sprint and MCI. Dedicated
models can also be used as a high speed modem for private twisted
pair. The Model 2500 Series is available in standalone or in rack-card
configurations (only standalone versions are covered in this manual).
1.3 FCC INFORMATION
The Model 2500 Series has been tested and registered in
compliance with the specifications in Part 68 of the FCC rules. A label
on the equipment bears the FCC registration number. You may be
requested to provide this information to your telephone company.
Your telephone company may make changes in its facilities,
equipment, operations or procedures that could affect the proper
operation of the Model 2500 Series. If this happens, the telephone
company should give you advance notice to prevent the interruption of
your service.
The telephone company may decide to temporarily discontinue
your service if they believe your Model 2500 Series may cause harm to
the telephone network. Whenever possible, they will contact you in
advance. If you elect to do so, you have the right to file a complaint with
the FCC.
If you have any trouble operating the Model 2500 Series, please
contact Patton Technical Support at [phone]. The telephone
company may ask you to disconnect the equipment from the telephone
network until the problem has been corrected or until you are certain
that the Model 2500 Series is not malfunctioning.
The following information may be required when applying to your
local telephone company for leased line facilities:
Service Digital Facility Service Order Network
Type Interface Code Code Jacks
2.4 Kbps Digital Interface 04DU5-24 6.0F RJ48S
4.8 Kbps Digital Interface 04DU5-48 6.0F RJ48S
9.6 Kbps Digital Interface 04DU5-96 6.0F RJ48S
56 Kbps Digital Interface 04DU5-56 6.0F RJ48S
(Note: As of this publication date, 19.2 and 64Kbps digital services
have not been assigned Digital Facility Interface Codes)
1.4 SERVICE INFORMATION
All warranty and non-warranty repairs must be returned freight
prepaid and insured to Patton Electronics. All returns must have a
Return Materials Authorization number on the outside of the shipping
container. This number may be obtained from Patton Electronics
Technical Service at [phone]. Packages received without an
RMA number will not be accepted.
Patton Electronics' technical staff is also available to answer any
questions that might arise concerning the installation or use of your
Model 2500 Series. Technical Service hours: 8AM to 5PM EST,
Monday through Friday.
3 4

3.0 INSTALLATION
This section describes connection of the Model 2500 Series to the
DTE and telco (line) interfaces, as well as AC power connection
3.1 DTE INTERFACE CONNECTION
The Model 2500 Series has connectors for both V.35 and RS-232
interfaces. Signals output by the Model 2500 Series will appear on
both interfaces. An internal jumper is used to select which interface will
be used for input. With the jumper in the factory default position, the
Model 2500 Series automatically selects which interface will be used for
input. If the DTR signal on the RS-232 is active, then the RS-232
inputs are selected. Otherwise, the V.35 inputs are selected. If you
choose, you may re-configure the Model 2500 Series for fixed V.35 or
fixed RS-232 operation. To do this, follow the steps below:
1) Turn the power switch off.
2) Remove the power cord from the unit.
3) Remove the two screws on the rear panel and slide the board
out from the rear.
4) Locate the DTE port selection jumper near the middle of the PC
board. This jumper has three pins, two of which are covered by
the strap. The factory position of the jumper is with the strap
covering the two pins closest to the rear of the unit.
5) To reconfigure the Model 2500 Series for fixed V.35 operation,
move the strap so that it covers the two pins closest to the front
of the unit.
6) To reconfigure the Model 2500 Series for fixed RS-232
operation, remove the strap altogether (be sure not to lose the
strap).
3.1.1 V.35 INTERFACE PORT
For V.35 operation, attach your DTE (terminal) cable to the 34 pin
rectangular M/34 connector. The DTE cable should be pinned
according to the diagram in Appendix D.
3.1.2 RS-232 INTERFACE PORT
For RS-232 operation, attach your DTE (terminal) cable to the 25
pin DB-25 connector. The DTE cable should be pinned according to
the diagram in Appendix D.
6
2.3 SUPPORTED APPLICATIONS
The Model 2500 Series includes three units: the Model 2500 All-
Rate CSU/DSU, the Model 2510 Switched 56 CSU/DSU and the Model
2520 All-Rate/Switched 56 CSU/DSU. Depending upon the unit
selected, the Mode 2500 Series supports three distinct modes of
operation. These are outlined in the descriptions and table below:
Dedicated DDS/Clear Channel Operation (Models 2500, 2520)
The unit can be easily configured for dedicated DDS/Clear Channel
operation by means of the dip switches on the bottom of the enclosure,
or by means of the software control port. Set the Line Rate to match
the rate of service to which you subscribe. Set the Mode switches for
Network Clocking. The Rate Converter and the Data Format options
should be set as required for your application. The remaining options
may need to be set depending on your terminal equipment and your
application.
Switched-56 Operation (Models 2510, 2520)
The unit can be used in Switched 56 applications. Set the Line
Rate to 56 kbps. Set the Mode switches for Switched 56, and enable
Force RTS and Circuit Assurance. Dial or store a number using the
control port. The Rate Converter and the Data Format options should
be set as required for your application. The remaining options may
need to be set depending on your terminal equipment and your
application.
Campus Area Short Haul Operation (Models 2500, 2520)
The unit can also be used for campus area point-to-point short-haul
applications on private twisted-pair wires. Set the Line Rates the same
on both units. Set the Mode switch for the appropriate Transmit Clock
Mode for your application. Internal, External and Looped Clock Modes
are available. Set the remaining options as needed by your terminal
equipment or your application.
5
MODEL 2500 SERIES APPLICATIONS
2500 2510 2520
Line Rate Switches All line rates 56 Kbps only All line rates
Supported Supported
Mode Switches Supports all modes Switched 56 only All modes
except Sw-56 Supported
Not Supported Supported Supported
Dialing
Comments

4.0 CONFIGURATION
Before you can operate your Model 2500 Series CSU/DSU, you
must configure the unit. Configuration may be done using the
externally accessible hardware switches or by using the software
switches. Software switches can be accessed from the front panel
control port using a VT-100 type RS-232 terminal that responds to ANSI
escape sequences.
4.1 CONFIGURATION USING HARDWARE SWITCHES
The Model 2500 Series defaults to the use of hardware switches for
configuration. The unit can also use software switches for configuration
(see Section 4.3), in which case the hardware switches will be ignored.
Note: If you are attempting to configure the unit using hardware
switches and find they are being ignored, you will need to override
the software switches and force the unit back into hardware switch
mode. To do this, power-up the unit once with the Line Rate (SW1-
1, 1-2, 1-3) set to Off, Off, Off. Then set the hardware switches as
you require and power-up the unit again.
The hardware configuration mode for the Model 2500 Series uses
sixteen externally accessible DIP switches. Figure 1 (below) shows the
location of the Model 2500 Series' DIP switches.
The Model 2500 Series’ DIP switches can be configured as either
“On” or “Off”. Figure 2 (opposite page) shows the orientation of the DIP
switches with respect to ON/OFF positions.
3.2 NETWORK INTERFACE CONNECTION
The Network Interface is an 8 position modular connector. Connect
this port to the RJ-48S jack provided by the digital data service
provider. If the Model 2500 Series is being used for private short haul
communication, the twisted pair cable will connect to this port. See
Appendix D for the pin assignments of this connector.
3.3 CONTROL PORT INTERFACE
The Control Port Interface is an 8 position modular connector. If it is
to be used, connect this port to an asynchronous terminal using a
shielded cable. See Section 4.4 for control port operation.
3.4 POWER
The model 2500 series has a built-in powers supply that is factory
configured for either 115 or 230 VAC, depending on how the product is
ordered. This power supply is equipped with a shrouded male IEC-320
power entry connector, and is available with a variety of domestic and
international power cords (see Appendix C).
In order for the Model 2500 Series unit to operate, the power cord
(supplied) must be attached to the power entry connector on the rear of
the unit and plugged into an outlet that is easily accessible. The power
switch on the rear of the unit must also be turned ON.
87
WARNING! There are no user-serviceable parts in the
power supply section of the Model 2500 Series. Voltage
setting changes and fuse replacement should only be
performed by qualified service personnel. Contact Patton
Electronics Technical support at [phone] for more
information.
Figure 1. Model 2500 Series bottom view, showing location of DIP switches
SW2
SW1

4.1.1 SWITCH SET SW1
The configuration switches on switch set SW1 allow you to specify
Line Rate, Circuit Assurance, RTS, Character Length, Data Format and
DSR Loop Status. Figure 3 (below) summarizes SW1 switch settings,
including the factory defaults. Following Figure 4 is a description of
each switch setting.
Line Rate
These switches control the signalling rate on the line (RJ-48S port).
They should match the speed of your digital service.
SW1-1 SW1-2 SW1-3 Setting
On On On 2.4 kbps
On On Off 4.8 kbps
On Off On 9.6 kbps
On Off Off 19.2 kbps
Off On On 56 kbps
Off On Off 64 kbps
Off Off Off Force configuration pointer to
default to hardware switches
(See Section 4.2)
(continued)
For line rates of 56 and 64 kbps, it is possible to operate the DTE
interface at a lower rate. To do this, set these switches to 56 or 64 kbps
and set the Rate Converter/DTE Rate switches as required.
Circuit Assurance
On dedicated circuits, the transmitter and the CTS output can be
configured to go On only when a working communication circuit is
established. If Circuit Assurance is used, enable it on only one end of
the communication link. In Switched 56 mode, this switch should be set
to On on both ends of the circuit.
Circuit
SW1-4 Assurance Description
On Enabled CTS will go low and the
transmitter will be held off if the
receiver is in the No Signal state
or CD is low
Off Disabled The transmitter and CTS will
operate without regard to the
receiver state
RTS
The RTS input can be forced on, ignoring the terminal’s RTS
signal. RTS controls the transmitter by either sending the user’s data or
sending an idle code. Force RTS should be enabled in Switched 56
mode.
SW1-5 RTS Description
Off Forced On An On (high) condition is trans-
mitted regardless of the state of
this unit’s RTS input
On Follows DTE The RTS input controls the
transmitter
Note: At 64K line rate, RTS is always Forced On.
9 10
ON
Figure 2. Close up of DIP switches showing ON/OFF positions.
SWITCH SET 1 SUMMARY TABLE
56,000 bps
}
Figure 3. Summary of switch settings, showing factory defaults
Position Function Factory Default
Switch SW1-1 Line Rate Off
Switch SW1-2 On
Switch SW1-3 On
Switch SW1-4 Circuit Assurance Off Disabled Model 2510 Enabled
Switch SW1-5 RTS Off Forced On
Switch SW1-6 Character Length Off 10 Bit
Switch SW1-7 Data Format Off Synchronous
Switch SW1-8 DSR Loop Status Off DSR Off

Character Length
In asynchronous data format, 10 and 11 bit characters are
supported. This setting is ignored in synchronous data format.
Character Character Description
SW1-6 Length Start Data bits Parity Stop bits
Off 10-bit 1 8 None 1 or more
1 7 1 1 or more
1 7 None 2
On 11-bit 1 8 1 1 or more
1 9 None 1 or more
Data Format
The data format selection controls whether an async-to-sync
conversion is performed. (Data is always transferred synchronously
between the two CSU/DSU’s)
SW1-7 Data Format
On Asynchronous
Off Synchronous
Note1:The async rate of 57.6 kbps is supported at the 56kbps line
rate, provided the DTE equipment transmits two stop bits. Two stop
bits can be configured on most DTE equipment. This extra stop bit
reduces the DTE’s effective data rate by a few percent to allow
synchronization with the 56kbps line speed.
Note2:Lower speed asynchronous data can be transmitted on
synchronous circuits by simple over-sampling. To do this, leave Data
Format set to synchronous. Make sure the CSU/DSU’s sync data rate
is at least 4 times more than the async data rate you wish to send.
DSR Loop Status
The behavior of the DSR output during performance of a local
loop can be controlled.
DSR
SW1-8 Loop Status Description
On DSR On DSR remains high (On) during the
Analog Loop
Off DSR Off DSR goes low (Off) during the
Analog Loop
4.1.2 SWITCH SET SW2
The configuration switches on switch SW2 control the Rate
Adapter/DTE Rate, Clock Mode, Anti-Stream Timer and RTS/CTS
Delay. Figure 5 (below) summarizes SW2 switch settings, including the
factory defaults. Following Figure 4 is a description of each switch
setting.
Rate Adapter/DTE Rate
The Model 2500 Series includes a rate adapter that allows the unit
to be used with DTE devices that support rates lower than 56/64 kbps.
All switch settings below are valid for line rates of 56 or 64 kbps.
SW2-1 SW2-2 SW2-3 DTE Rate
On On On 2.4 kbps
Off On On 4.8 kbps
On Off On 9.6 kbps
Off Off On 19.2 kbps
On On Off 38.4 kbps
Off Off Off Line Rate = DTE Rate
Note: for DTE devices that operate at 57.6 kbps, set the Line Rate to
56 kbps (see Section 4.1.1), set the rate adapter for “Line Rate=DTE
Rate”, and configure your DTE device for two stop bits (set character
length accordingly).
1211
SWITCH SET 2 SUMMARY TABLE
Figure 4. Summary of switch settings, showing factory defaults
Position Function Factory Default
Switch SW2-1 Rate Adapter/ Off
Switch SW2-2 DTE Rate Off
Switch SW2-3 Off
Switch SW2-4 DTE Loop Control Off Disabled
Switch SW2-5 Clock Mode Off Off
Switch SW2-6 Off On
Switch SW2-7 Anti-Stream Timer On Disabled
Switch SW2-8 RTS/ CTS Delay Off Normal
Model 2510
Switched 56
}
Network
Clock
}
DTE Rate
}

DTE Loop Control
The local loop and remote loop can be activated from the DTE
interface using signals “LL” and “RL”.
SW2-4
On Enable LL and RL inputs
Off Disable
Clock Mode
The appropriate transmitter clocking modes can be selected for
Dedicated DDS, Switched-56 or campus-area (private) operation.
SW2-5 SW2-6 Mode Description
On Off External Clock Mode Transmit Clock derived
from terminal interface
Off Off Network Clock Mode Transmit clock derived
(Looped Clock Mode) from the received line
signal; Use this mode
for Dedicated DDS
operation
On On Internal Clock Mode Transmit Clock derived
internally
Off On Switched 56 (Model 2510, 2520)
Anti-Stream Timer
The anti-stream timer protects multidrop networks from a drop that
is continuously transmitting. If the terminal keeps RTS raised for more
than 30 seconds, the timer forces RTS off internally. This allows the
rest of the multidrop network to resume operation. The CSU/DSU
remains in the forced-off condition until the terminal drops RTS.
Timer Value in Sec at Various Line Rates
SW2-7 Timer 56 19.2 9.6 4.8 2.4
On Disabled
Off Enabled 2 4 8 15 30
CTS Delay
The RTS/CTS turn-on delay can be set to Normal or Extended.
Delay in mSec at Various Line Rates
SW2-8 CTS Delay 56 19.2 9.6 4.8 2.4
Off Normal 0.3 0.9 1.9 3.8 7.5
On Extended 1.3 3.8 7.5 15 30
4.2 CONFIGURATION USING SOFTWARE SWITCHES
The Model 2500 Series CSU/DSUs can be soft configured using a
VT100 terminal or similar RS-232 DTE with terminal emulation. To use
software switches for configuration, follow these steps:
1) Connect the serial RS-232C port of the terminal to the modular
EIA-561 control port on the front panel of the Model 2500 Series.
To construct an RS-232 to EIA-561 patch cable, refer to the control
port pinout diagram in Appendix D.
2) Power up the terminal and set its RS-232C port as follows:
9600 baud
8 data bits, 1 stop bit, no parity
local echo
CR = CR/LF on inbound data
ANSI, VT-100 emulation
3) Key menu, then press [RETURN]. The Model 2500 Series
Main Menu should then display on the terminal screen (see below).
13 14

4.2.1 USING THE SOFTWARE MENU SYSTEM
The Model 2500 Series Menu System operates as follows:
1) All selections must be followed by [RETURN].
2) To make a selection from any menu, enter the option number at
the prompt and press [RETURN].
3) To exit any menu without making a selection, press [ESC]
followed by [RETURN]. (Note: You can also exit by just pressing
[RETURN]. However, doing this in the Store Phone Number Menu
will clear the buffer of the currently stored number.)
4.2.2 VERIFYING SOFTWARE SWITCH CONTROL
In order to use software switches for configuration, it is necessary to
disable the hardware switch settings. To do this, use the following
procedure (Note: If this procedure is omitted, your software
configurations will be overridden by the hardware switch settings):
1) On the Main Menu (opposite page), choose item 1, “Select
Hardware/Software Switch Control”. The following screen will appear:
2) In the Hardware/Software Control Menu, select item 2 to enable
software switch control.
3) The Main Menu will automatically reappear after your selection is
entered.
15 16
4.2.3 SETTING SOFTWARE SWITCH PARAMETERS
From the Main Menu, selecting item 3, “Set Software Switch
Parameters” will take you to the Software Switch Menu (below). From
this screen, you can select any parameters that you wish to soft
configure.
For each screen described below, selecting a numbered option and
pressing [RETURN] stores that option setting and returns you to the
Software Switch Menu (Note: All lettered options must be entered in
lower case).
Line Rate
Choosing option 1 in the Software Switch Menu takes you to the
Line Rate Menu (below). This option controls the signaling rate on the
line. Set it to match the speed of your digital service. For line rates of
56 or 64 kbps, it is possible to operate the DTE interface at a lower rate.
To do this , set the line rate to 56 or 64 kbps. Then set the DTE Speed
as required (Software Switch Menu option 7).

Character Length
Choosing option 4 in the Software Switch Menu takes you to the
Character Length Menu (below). In asynchronous data format, the
Model 2500 Series supports 10-bit and 11-bit character lengths. Set
this option according to the characteristics of the data being
transmitted.
DTE Data Format
Choosing option 5 in the Software Switch Menu takes you to the
Data Format Menu (below). This option controls whether an async-to-
sync conversion is performed between the DTE and the Model 2500
Series. (Data is always transferred synchronously between two Model
2500 Series units.) For an asynchronous DTE, select the
asynchronous data format1,2; for a synchronous DTE, select the
synchronous data format.
Note1:The async rate of 57.6 kbps is supported at the 56 kbps line
rate, provided the DTE equipment transmits two stop bits. Two stop bits
can be configured on most DTE equipment. This extra stop bit reduces
the DTE’s effective data rate by a few percent to allow synchronization
with the 56 kbps line speed. Set the Model 2500 Series for two stop
bits by selecting “11 bit character length” in the Character Length Menu.
(continued)
Circuit Assurance
Choosing option 2 in the Software Switch Menu takes you to the
Circuit Assurance Menu (below). On dedicated (DDS) circuits, the
transmitter and the CTS output can be configured to go ON only when a
working communication circuit is established. If you use Circuit
Assurance with DDS services, enable it on only one end of the
communication link. For Switched-56 service, enable Circuit Assurance
on both ends of the circuit. When Circuit Assurance is disabled, the
transmitter and CTS operate without regard to the receiver state.
Force RTS
Choosing option 3 in the Software Switch Menu takes you to the
RTS Menu (below). The RTS input can be forced ON, ignoring the RTS
signal from the DTE. RTS controls the transmitter by sending either
user data (when high) or idle code (when low). On a Model 2510 or
2520, Force RTS should be enabled for Switched-56 operation.
Note: When the Line Rate (Software Switch Menu option 1) is 64 kbps,
RTS is always forced ON, regardless of the Force RTS switch setting.
17 18

Note2:You can use the Model 2500 Series to transmit lower-speed
asynchronous data (up to 9.6 kbps) over synchronous circuits by simple
over-sampling. To do this, select the synchronous data format and set
the line Line Rate (Software Switch Menu option 1) to at least four times
that asynchronous data rate you wish to send. For example, use a Line
Rate of 9.6 kbps or higher for 2.4 kbps async data.
DSR Status During Local Loopback
Choosing option 6 in the Software Switch Menu takes you to the
DSR Loop Status Menu (below). This option controls the behavior of
the DSR output during local loopback. To force DSR high (ON) during
local loopback, enable this option. To force DSR low (OFF) during a
local loopback, disable it.
Rate Converter/DTE Rate
Choosing option 7 in the Software Switch Menu takes you to the
Rate Adapter/DTE Rate Menu (opposite page). The Model 2500 Series
rate converter adapts a 56 kbps or 64 kbps line rate to slower DTE data
rates. Set the Rate Converter to match the DTE data rate. If the DTE
data rate is the same as the line rate, disable rate conversion by
selecting item 6 on this menu.
(continued)
19 20
Note: For DTE data rates of 56 kbps or 64 kbps, set the rate adapter to
“Line Rate = DTE Rate”, and the line rate to 56 or 64 kbps, respectively.
For DTE rate of 57.6 kbps, set the rate adapter to “Line Rate =
DTE Rate”, set line rate to 56 kbps, set DTE for two stop bits, and set
CSU/DSU character length to “11 bits”.
DTE Loop Control
Choosing option 8 in the Software Switch Menu takes you to the
DTE Loop Control Menu (below). The local and remote loopbacks on
the Model 2500 Series can be controlled from the DTE interface by
raising or lowering the LL and RL signals. To allow the DTE to control
these loopbacks in this manner, enable this option. Disable if you want
the Model 2500 Series to ignore these signals.
(continued)

21 22
Clock Mode
Choosing option 9 in the Software Switch Menu takes you to the
Clock Mode Menu (below).
Set this option as follows:
• Internal (Master): To use the Model 2500 Series internal reference
clock as the timing source, select item 1. Use internal timing in point-to-
point applications where the Model 2500 Series is being used as a
limited distance modem. (Set the far-end Model 2500 Series unit for
looped timing as described below.)
• Network (Looped): To have the Model 2500 or 2520 derive a
transmit clock from the incoming data stream from the network, select
item 2. This is the default setting and appropriate for most applications.
• External (Terminal Timing): To have the Model 2500 Series use the
DTE-supplied transmit clock (pin 24 on and RS-232/V.24 interface or
pins U and W on a V.35 interface), select item 3. Use external timing
for tail-circuit applications, in which the RS-232 or V.35 ports of two
Model 2500 Series units are interconnected.
• Switched 56 (Model 2510 and 2520 only): When using a Model
2510 or 2520 with Switched 56 service, select item 4.
(continued)
Anti-Streaming Timer
Choosing option “a” in the Software Switch Menu takes you to the
Anti Stream Timer Menu (below). (Note: You must use lower case
letters for options “a” thru “e”) This option lets you enable or disable the
anti-streaming timer, which protects multidrop networks from a drop that
is continuously transmitting. If the DTE asserts RTS for a period of time
exceeding the timer interface, the timer forces RTS off internally. This
allows the rest of the multidrop network to resume operation. The
Model 2500 Series holds RTS off until the terminal drops RTS. The
timer interval decreases as the line rate increases.
RTS/CTS Delay
Choosing option “b” in the Software Switch Menu takes you to the
RTS/CTS Delay Menu (below). This option lets you set the RTS/CTS
turn-on delay to Normal or Extended. The delay interval decreases as
the line rate increases.

5.0 OPERATION
Once the Model 2500 Series unit is installed and configured
properly it is ready to operate. This section describes the function of
the LED indicators, the status displays, the use of loopback test modes,
and Switched 56 dialing procedures (Models 2510 and 2520 only).
5.1 LED DESCRIPTIONS
The Model 2500 Series is equipped with nine LED indicators that
monitor the status of communication. Figure 5 (below) shows the
location of the LEDs on the Model 2500 Series front panel. Note also
the location of the test mode switches and RS-232 control port (used in
Switched 56 dialing as well as software configuration). Following Figure
5 is a description of each LED’s function.
• “TD” and “RD” will glow red to indicate an Idle condition or
Binary “1” data on the respective terminal interface signals.
Green indicates Binary “0” data.
• “CTS” will glow red to indicate an Off condition. Green
indicates an On condition. When on, the unit is ready to send
data. If CTS remains off, check the Forced RTS, Circuit
Assurance and Anti-Stream settings.
• “CD” will glow green to indicate that the a valid carrier is
present. Red indicates that there is no valid carrier detected.
• “DTR” will glow green to indicate that the DTR signal from the
terminal is active.
• “NS” will glow red to indicate No Signal. This means the
Model 2500 Series receiver does not detect a signal from the
digital service provider (or, in the case of short-haul operation,
from the remote Model 2500 Series). If NS is lit, check for an
unplugged cable, broken wire or an incorrect Line Rate
selection. (continued)
• “OS” glows red to indicate Out-of-Service. This means the
Model 2500 Series has received an Out-of-Service signal from
the digital service provider and indicates a problem with the
service provider’s equipment. If this condition persists, contact
your service provider.
• “ER” glows red to indicate that an error has been detected in
the received signal. ER will flash if the Model 2500 Series
receives illegal bi-polar violations or framing errors. During the
511 or 511/E test, ER will flash to indicate that the Test Pattern
Detector has detected a bit error.
• “TM” glows red to indicate Test Mode. It will light if the unit is
placed into a test mode. The unit can be placed in test mode
by the local user, by the remote user or by the service
provider.
5.2 STATUS DISPLAYS
The Model 2500 Series lets you use a VT-100 type RS-232 terminal
to display the current configuration settings, as well as the line/loop
status.
5.2.1 DISPLAYING CONFIGURATION SETTINGS
To display the current settings of the hardware and /or software
switches, go to the Main Menu (see Section 4.2) and select item 2,
“Read Configuration”. This will take you to the Read Configuration
Menu (below).
(continued)
23 24
Figure 5. The Model 2500 Series' front panel LEDs

25 26
In the Read Configuration Menu, you may select item 1 to read the
hardware switch configuration or item 2 to read the software switch
configuration. A sample screens is shown below:
5.2.2 DISPLAYING LINE/LOOP STATUS
To check the current status of the Model 2500 Series and the
associated circuit, go to the Main Menu (see Section 4.2) and select
item 4, “Display Line/Loop Status”1,2. This will take you to a screen
similar to the Line/Loop Status Monitor Screen (below).
Note1:To refresh the display with the most up-to-date information, key
“4” and press [RETURN].
Note2:The error count is reset after each time it is displayed.
5.3 LOOPBACK TEST MODES
The Model 2500 Series offers three loopback tests to evaluate the
condition of the CSU/DSUs and the communication link: local analog
loopback, remote digital loopback and telco loopback (C.O. Loopback).
5.3.1 LOCAL ANALOG LOOPBACK (LAL)
The Local Analog Loopback (LAL) test checks the operation of the
local Model 2500 Series. Any data sent to the local Model 2500 Series
in this test mode will be echoed (returned) back to the user device. For
example, characters typed on the keyboard of a terminal will appear on
the terminal screen (see Figure 6, below).
LAL Test Activation
The LAL test may be activated in one of three ways:
1) Toggle the front panel “Local/Normal/Remote” switch UP to the
“Local” position.
2) Activate the LL lead from the DTE (Note: in order to use this
option, the DTE Loop Control option must be enabled–see
Section 4.1.2). If you are not sure which pin is the LL lead, please
refer to the pinout diagrams in Appendix D.
3) From a terminal, first go to the Main Menu and select item 3 to
display the Software Switch Menu (Section 4.2) In the Software
Switch Menu, select item “e” to go to the Local Line Loop Menu
(see below). To activate LAL, select item 1.
Figure 6. Local analog loop

27 28
LAL Test Procedure
Once LAL is activated, the Model 2500 Series transmit output is
connected to its own receiver. The “Test” LED should be lit. Follow
these steps to complete the test:
1) Verify that the data terminal equipment is operating properly and
can be used for a test. If a fault is indicated, call a technician or
replace the unit.
2) Perform a BER (bit error rate) test on each unit using a separate
BER tester (The Model 2500 Series has a built-in BER tester–see
Section 5.4). If the BER test equipment indicates no faults but the
data terminal indicates a fault, follow the manufacturer's checkout
procedures for the data terminal. Also, check the interface cable
between the terminal and the Model 2500 Series.
5.3.2 REMOTE DIGITAL LOOPBACK (RDL)
The Remote Digital Loopback (RDL) test checks the performance of
both the local and remote Model 2500 Series', and the communication
link between them. Any characters sent to the remote Model 2500
Series in this test mode will be returned back to the originating device.
For example, characters typed on the keyboard of the local terminal will
appear on the local terminal screen after having been passed to the
remote Model 2500 Series and looped back (see Figure 7, below).
RDL Test Activation
The RDL test may be activated in one of three ways:
1) Toggle the front panel “Local/Normal/Remote” switch DOWN to
the “Remote” position.
(continued)
2) Activate the RL lead from the DTE (Note: in order to use this
option, the DTE Loop Control option must be enabled–see
Section 4.1.2). If you are not sure which pin is the RL lead, please
refer to the pinout diagrams in Appendix D.
3) From a terminal, first go to the Main Menu and select item 3 to
display the Software Switch Menu (Section 4.2) In the
Software Switch Menu, select item “d” to go to the Set
Remote Digital Loop Menu (see below). To activate RDL, select
item 1.
RDL Test Procedure
Once LAL is activated, the “Test” LED should be lit. Perform a BER
(bit error rate) test on the system, using BER testers on both ends. If
the BER test equipment indicates a fault and the Local Analog
Loopback test was successful for both Model 2500 Series units, you
may have a problem with the line between the CSU/DSUs. You should
inspect the line for proper connections.
5.3.3 TELCO TESTING
The digital service provider’s central office can perform CSU Loop
and DSU Loop diagnostic testing. These diagnostics allow the central
office to evaluate circuit operation without making visits to a customer’s
premises.
(continued)
Figure 7. Remote digital loop

29 30
CSU Loop
The CSU Loop is activated when the central office reverses the DC
sealing current that flows between the TX pair and the RX pair. In this
case, the Model 2500 Series recognizes this and loops signals on the
RX pair back to the central office on the TX pair (see Figure 8, below).
While the CSU Loop is activated by the central office, the TM light is
illuminated.
DSU Loop
The DSU Loop is activated when the central office sends a DSU
loop signal over the twisted pair wire. The Model 2500 Series senses
this signal and loops the digital data back to the central office (see
Figure 9, below). While the DSU Loop is activated, the TM light is
illuminated.
5.4 THE V.52 BER TEST PATTERN GENERATOR
The Model 2500 Series has a built-in test pattern generator and
detector. It can be invoked at both ends of a link simultaneously (using
two operators) or it can be invoked in conjunction with the LAL or RDL
tests (using one operator). The following example requires two
operators–one to initiate and monitor the test at the local Model 2500
Series, and one at the remote Model 2500 Series. To use the V.52 BER
test by itself, both operators should simultaneously follow these steps:
(continued)
1) Locate the “511/511E” toggle switch on the front panel of the
Model 2500 Series and move it DOWN (see Note 1). This
activates the V.52 BER test mode and transmits a “511”
pseudorandom test pattern to the other unit. If any errors are
received, the receiving CSU/DSU’s red “Error” LED will blink
sporadically (see Notes 1 & 2, below).
2) If the test indicates no errors are present, move the V.52 toggle
switch UP, activating the “511/E” test (see Note 2). The 511/E test
transmits the 511 pseudorandom test pattern and injects
intentional errors about once per second. If the test is working
properly, the receiving CSU/DSU’s red “Error” LED will blink
regularly.
A successful “511/E” test will confirm that the link is in place, and
that the Model 2500 Series’ built-in “511” generator and detector
are working properly.
Note1: The 511 BER pattern can also be activated using the
software control port. Follow these steps: From a
terminal, first go to the Main Menu and select item 3 to
display the Software Switch Menu (Section 4.2) In the
Software Switch Menu, select item “c” to go to the Send
511 Pattern Menu (see below). To send a 511 pattern,
select item 1.
Note2:Control Port activation of the “511E” pattern is not
possible. The “511E” pattern may only be activated using
the front panel toggle switch.
Figure 9. DSU loop
Figure 8. CSU loop

31 32
5.5 SWITCHED 56 DIALING COMMANDS (MODELS 2510 & 2520)
To access the Switched 56 dialing capabilities of the Mode 2500
Series, go to the Main Menu (see Section 4.2) and select item 5, “Set
Switched 56 Dialing Parameters”. This will take you to the Switched 56
Menu (see below). The following paragraphs describe the commands
in the Switched 56 Menu.
Store Phone Number (Enable DTR Dialing)
Selecting item 1 in the Dial Menu lets you activate the Model 2500
Series’ “DTR Dialing” feature by storing a phone number in the unit’s
non-volatile memory. The Model 2500 Series automatically dials this
number when the DTE raises the DTR lead. When you issue this
command, the Model 2500 Series responds with this prompt:
Enter up to 12 digits (without hyphens or other alphabetic characters),
followed by [RETURN]. For example: “13015551212.”
Note: To disable DTR dialing, press [RETURN] (and nothing else)
when asked to enter the number to be stored.
(continued)
Read Stored Number
Selecting item 2 in the Dial Menu lets you view the phone number
currently stored in the Model 2500 Series non-volatile memory.
Dial New Number
Selecting item 3 in the Dial Menu lets you dial a number other than
the one stored in non-volatile memory. When you select this menu
item, the Model 2500 Series responds with this prompt:
Enter up to 12 digits (without hyphens or other alphabetic characters),
followed by [RETURN]. For example: “13015551212.”
After dialing the number, the Model 2500 Series will display the
message, “Dialing” and then display each number as it is dialed. The
Model 2500 Series will then prompt the user to wait while the
connection is made. One of the following messages will then be
displayed to indicate the success or failure or the connection:
•CONNECT: The called unit has answered.
•NO WINK: The central office did not send a wink signal
within 5 seconds of line seizure.
•SHORT WINK: A wink signal less than 120 milliseconds
was received.
•LONG WINK: A wink signal greater than 320 milliseconds
was received.
•NO CARRIER: The called unit did not answer within 30
seconds.
•DTR OFF: DTR must be on to dial.
•OFF HOOK: The Model 2500 Series is already off-hook and
in data mode.
Note: The control port will not respond to additional commands until
one of the above response messages is issued.
Hang Up
Selecting item 4 in the Dial Menu terminates the call.
CAUTION! For proper Switched 56 operation, you must enable
the Circuit Assurance and Force RTS options as described in
Section 4.0. Failure to do so may prevent the Model 2500
Series unit from answering incoming Switched 56 calls.
CAUTION! Pressing [RETURN] by itself will erase any
previously stored number from the unit’s non-volatile memory
and cannot be undone. This will also disable DTR dialing.

33 34
APPENDIX A
SPECIFICATIONS
DDS Type: Dedicated
Transmission Format: Asynchronous, synchronous
Interface: RS-232 and V.35
Standards: AT&T 62310 compliant
DDS Line Rates: 2.4, 4.8, 9.6, 19.2, 56 and 64 kbps
DTE Rates: 2.4, 4.8, 9.6, 19.2, 38.4, 56, and 64 kbps; 57.6 kbps,
async, 2 stop bits
Control Port: Configuration and diagnostics
Transmission Line: 4-wire
Applications: DDS point-to-point or multipoint; campus-area point-to-
point
Indicators: LED indicators for TD, RD, CTS, CD, DTR, No Signal, Out-
of-Service, Error and Test Mode
Diagnostics: V.54 compliant local and remote loopback tests; V.52
compliant 511/511E BER test, TELCO CSU and DSU loops
Connectors: DB-25 and M/34
Power Supply: 115V or 230V AC
Dimensions: 7.3” x 6.6” x 1.6”
APPENDIX B
CABLE RECOMMENDATIONS
The Patton Model 2500 Series operates at frequencies of 20kHz or
less and has been performance tested by Patton technicians using
twisted-pair cable with the following characteristics:
Wire Gauge Capacitance Resistance
19 AWG 83nf/mi or 15.72 pf/ft. .0163 Ohms/ft.
22 AWG 83nf/mi or 15.72 pf/ft. .0326 Ohms/ft.
24 AWG 83nf/mi or 15.72 pf/ft. .05165 Ohms/ft.
To gain optimum performance from the Model 2500 Series, please
keep the following guidelines in mind:
• Always use twisted pair wire—this is not an option.
• Use twisted pair wire with a capacitance of 20pf/ft or less.
• Avoid twisted pair wire thinner than 26 AWG (i.e. avoid higher
AWG numbers than 26)
• Use of twisted pair with a resistance greater than the above
specifications may cause a reduction in maximum distance
obtainable. Functionality should not be affected.
• Many environmental factors can affect the maximum distances
obtainable at a particular site. Use the above data rate/distance
table as a general guideline only.
Data
Rate
64 Kbps 7.1 4.9 3.4
56 Kbps 7.6 5.2 3.6
19.2 Kbps 8.7 6.2 4.5
9600 bps 10.4 7.7 5.8
4800 bps 13.7 10.6 9.7
2400 bps 15.1 14.2 9.1
Model 2500 Series Distance Table (miles)
Wire Gauge
22 24 26

35 36
APPENDIX C
FACTORY REPLACEMENT PARTS
AND ACCESSORIES
Patton Model # Description
10-2500...........................DDS Cable, RJ48 - RJ48, 6 foot
10-561S...........................Control Port Cable, EIA-561, 6ft, shielded
12M-561..........................Adapter, EIA-561 to DB-25 Male
12F-561...........................Adapter, EIA-561 to DB-25 Female
082R2..............................Fuse 5x20mm, 200mA, 250V, Time-lag
Little Fuse P/N 239.200
0805US ...........................American Power Cord
0805EUR.........................European Power Cord CEE 7
0805EURP ......................Europlug Power Cord CEE 7/16
0805UK ...........................United Kingdom Power Cord
0805AUS.........................Australia/New Zealand Power Cord
0805DEN.........................Denmark Power Cord
0805FR............................France/Belgium Power Cord
0805IN.............................India Power Cord
0805IS.............................Israel Power Cord
0805JAP..........................Japan Power Cord
0805SW...........................Switzerland Power Cord
APPENDIX D
INTERFACE PIN ASSIGNMENT
DDS INTERFACE
The DDS Interface is an RJ-48S modular jack.
Pin # Signal
1 TX+
2 TX-
3 no connection
4 no connection
5 no connection
6 no connection
7 RX+
8 RX-
M/34 CONNECTOR, TERMINAL INTERFACE
Pin # Signal
B SGND (Signal Ground)
C RTS
D CTS
E DSR
F CD
H DTR
L LL (Local Loop)
M TM (Test Mode)
N RL (Remote Loop)
P TD
R RD
S TD/
T RD/
U XTC
V RC
W XTC/
X RC/
Y TC
AA TC/

(APPENDIX D - Continued)
DB-25 CONNECTOR, TERMINAL INTERFACE
Pin # Signal
1 Frame Ground
2 TD
3 RD
4 RTS
5 CTS
6 DSR
7 SGND (Signal Ground)
8 CD
15 TC
17 RC
18 LL (Local Loop)
20 DTR
21 RL (Remote Loop)
24 XTC
25 TM (Test Mode)
CONTROL PORT INTERFACE
8 Position modular connector compliant with EIA-561.
Pin # Signal
4 Signal Ground
5 RD (Output)
6 TD (Input)
APPENDIX E
TRANSMITTER CLOCK SOURCE DURING TEST LOOPS
RC = Received Clock
37 38
Analog Originating Receiving
Clock Mode Normal Loop Remote Loop Remote Loop
Internal INT INT INT RC
External EXT INT EXT EXT
Network RC INT RC RC