Patton electronic Switch 2701 I User Manual

USER

MANUAL

MODEL 2701/I

G.703/G.704 NTU with

10Base-T Ethernet

Interface

Important—This is a Class A device and is

intended for use in a light industrial environ-

ment. It is not intended nor approved for use

in an industrial or residential environment.

Part# 07M2701I-UM

Doc# 08609U2-001

Rev. I

SALES OFFICE

(301) 975-1000

TECHNICAL SUPPORT

(301) 975-1007

Revised 2/18/08

An ISO-9001Certiﬁed

Company

Specifications ........................................................................... 26

A.1 Network Data Rate ...................................................................... 26

A.2 Network Connector ..................................................................... 26

A.3 Nominal Impedance ................................................................... 26

A.4 Line Coding ................................................................................ 26

A.5 Line Framing ............................................................................... 26

A.6 CRC-4 Multiframing .................................................................... 26

A.7 Clocking ...................................................................................... 26

A.8 Time Slot Rate ............................................................................. 26

A.9 Network Data Rates .................................................................... 26

A.10 Distance ...................................................................................... 26

A.11 Power Supply .............................................................................. 26

A.12 Humidity ...................................................................................... 27

A.13 Temperature ............................................................................... 27

A.14 Dimensions ................................................................................. 27

Ethernet 10Base-T Specifications........................................... 28

B.1 DTE Interface .............................................................................. 28

B.2 DTE Data Rates .......................................................................... 28

B.3 LAn Connection .......................................................................... 28

B.4 Protocol ....................................................................................... 28

B.5 MAC Address Table Size ............................................................ 28

B.6 MAC Address Aging ................................................................... 28

B.7 Frame Buffer ............................................................................... 28

B.8 Frame Latency ............................................................................ 28

B.9 Diagnostics ................................................................................. 28

B.10 Indicators .................................................................................... 28

B.11 Configuration .............................................................................. 28

Factory Replacement Parts and Accessories........................ 29

1.0 WARRANTY & COMPLIANCE INFORMATION

Patton Electronics warrants all Model 2701/I 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. 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 specif-

ically disclaims all other warranties, expressed or implied, and the instal-

lation or use of this product shall be deemed an acceptance of these

terms by the user.

1.1 COMPLIANCE

EMC Compliance

• EN55022, Class A

• EN55024

Safety Compliance:

• EN 60950-1

• AS/NZS 60950-1

PSTN Regulatory Compliance:

• TBR 12 & 13

• AS/ACIF S016:2001

1.2 CE NOTICE

We certify that the apparatus identiﬁed in this document conforms to the

requirements of Council Directive 1999/5/EC on the approximation of the

laws of the member states relating to Radio and Telecommunication Ter-

minal Equipment and the mutual recognition of their conformity.

The safety advice in the documentation accompanying this product shall

be obeyed. The conformity to the above directive is indicated by the CE

sign on the device.

1.3 AUTHORIZED EUROPEAN REPRESENTATIVE

D R M Green

European Compliance Services Limited.

Oakdene House, Oak Road

Watchﬁeld, Swindon, Wilts SN6 8TD, UK

1.4 SERVICE

All warranty and nonwarranty repairs must be returned freight prepaid

and insured to Patton Electronics. All returns must have a Return Mate-

rials Authorization number on the outside of the shipping container. This

number may be obtained from Patton Electronics Technical Services at:

• Tel: +1 (301) 975-1007

• Email: [email protected]

• URL: http://www.patton.com

Note Packages received without an RMA number will not be

accepted.

Patton Electronics' technical staff is also available to answer any ques-

tions that might arise concerning the installation or use of your Patton

Model 2701/I. Technical Service hours: 8AM to 5PM EST, Monday

through Friday.

1.5 SAFETY WHEN WORKING WITH ELECTRICITY

• This device contains no user serviceable parts. The

equipment shall be returned to Patton Electronics for

repairs, or repaired by qualiﬁed service personnel.

• The external power adapter shall be a listed Limited

Power Source. Ensure that the power cable used meets

all applicable standards for the country in which it is to

be installed, and that it is connected to a wall outlet

which has earth ground. The mains outlet that is uti-

lized to power the devise shall be within 10 feet (3

meters) of the device, shall be easily accessible, and

protected by a circuit breaker.

WARNING

• Hazardous network voltages are present in WAN ports

regardless of whether power to the unit is ON or OFF. To

avoid electric shock, use caution when near WAN ports.

When detaching the cables, detach the end away from

the device ﬁrst.

• Do not work on the system or connect or disconnect

cables during periods of lightning activity.

In accordance with the requirements of council direc-

tive 2002/96/EC on Waste of Electrical and Electronic

Equipment (WEEE), ensure that at end-of-life you sepa-

rate this product from other waste and scrap and deliver

to the WEEE collection system in your country for recy-

cling.

This device is not intended to be connected to the public

telephone network.

WARNING

2.0 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 Pat-

ton Electronics Technical Support at (301) 975-1007.

2.1 FEATURES

• Terminates G.703 and G.704, E1/fractional E1 service

• Available in low-cost standalone or rack-mountable versions

• n x 64 kbps data rates to 2.048 Mbps

• 10Base-T Ethernet bridge

• PPP (Point to Point Protocol, RFC 1661) with Bridge Control Protocol

(RFC 1638)

• 75-ohm dual coax and 120-ohm twisted-pair G.703 connections

• Local and remote loopback diagnostics

• Internal and G.703 network timing

• CE approval

• 90-260VAC & 48VDC power options

• Conforms to ONP requirements CTR 12 and CTR 13 for connection to

international Telecom networks

2.2 DESCRIPTION

The Model 2701/I receives channelized G.704 (n x 64kbps) or clear

channel E1/G.703 (2.048-Mbps) data from the telco's digital data net-

work. The Model 2701/I terminates the G.703 telco interface and con-

verts the data for transmission to a user-oriented 10Base-T (802.3)

Ethernet interface.

The Ethernet (Model 2701/I) supports an integrated 10Base-T (802.3)

Ethernet port with transparent bridging capability for IP, IPX, DECnet,

NetBIOS and other layer-3 protocols. The 2701/I attaches to the LAN

and intelligently bridges data trafﬁc to the large central site router

through the telco's leased line network. The 2701/I supports PPP (RFC

1661) and BCP (RFC 1638).

The Model 2701/I is a 10Base-T bridge that operates over G.703/G.704

lines. It uses MAC learning and forwarding to provide seamless LAN-to-

LAN connectivity. As a result, corporate enterprises can connect their

servers to a pair of NTUs and automatically forward data packets that are

meant for the remote network. Local packets are ﬁltered and passed only

to the local LAN.

3.0 PPP OPERATIONAL BACKGROUND

PPP is a protocol used for multi-plexed transport over a point-to-point

link. PPP operates on all full duplex media, and is a symmetric peer-to-

peer protocol, which can be broken into three main components: 1. A

standard method to encapsulate datagrams over serial links; 2. A Link

Control Protocol (LCP) to establish, conﬁgure, and test the data-link con-

nection; 3. A family of Network Control Protocols (NCPs) to establish and

conﬁgure different network layer protocols.

In order to establish communications over a point-to-point link, each end

of the PPP link must ﬁrst announce its capabilities and agree on the

parameters of the link’s operation. This exchange is facilitated through

LCP Conﬁgure-Request packets.

Once the link has been established and optional facilities have been

negotiated, PPP will attempt to establish a network protocol. PPP will

use Network Control Protocol (NCP) to choose and conﬁgure one or

more network layer protocols. Once each of the network layer protocols

have been conﬁgured, datagrams from the established network layer

protocol can be sent over the link. The link will remain conﬁgured for

these communications until explicit LCP or NCP packets close the link

down, or until some external event occurs.

The PPP Bridging Control Protocol (BCP), deﬁned in RFC 1638, conﬁg-

ures and enables/disables the bridge protocol on both ends of the point-

to-point link. BCP uses the same packet exchange mechanism as the

Link Control Protocol (LCP). BCP is a Network Control Protocol of PPP,

bridge packets may not be exchanged until PPP has reached the net-

work layer protocol phase.

3.1 APPLICATIONS

In situations where a routed network requires connectivity to a remote

Ethernet network, the interface on a router can be conﬁgured as a PPP

IP Half Bridge. The serial line to the remote bridge functions as a Virtual

Ethernet interface, effectively extending the routers serial port connec-

tion to the remote network. The bridge device sends bridge packets

(BPDU's) to the router's serial interface. The router will receive the layer

three address information and will forward these packets based on its IP

address.

Figure 1 shows a typical Cisco router with a serial interface conﬁgured

as a PPP Half Bridge. The router serial interface uses a remote device

that supports PPP bridging to function as a node on the remote Ethernet

network. The serial interface on the Cisco will have an IP address on the

same Ethernet subnet as the bridge.

Figure 1. Cisco router with serial interface, conﬁgured as PPP Half Bridge.

For example, the customer site is assigned the addresses 192.168.1.0/

24 through 192.168.1.1/24. The address 192.168.1.1/24 is also the

default gateway for the remote network. The above settings remove any

routing/forwarding intelligence from the CPE. The associated Cisco con-

ﬁguration will set serial interface (s0) to accommodate half bridging for

the above example.

Authentication is optional under PPP. In a point-to-point leased-line link,

incoming customer facilities are usually ﬁxed in nature, therefore authen-

tication is generally not required. If the foreign device requires authenti-

cation via PAP or CHAP, the PPP software will respond with default Peer-

ID consisting of the units Ethernet MAC address and a password which

consists of the unit’s Ethernet MAC address.

Some networking systems do not deﬁne network numbers in packets

sent out over a network. If a packet does not have a speciﬁc destination

network number, a router will assume that the packet is set up for the

local segment and will not forward it to any other sub-network. However,

in cases where two devices need to communicate over the wide-area,

bridging can be used to transport non-routable protocols.

Figure 2 illustrates transparent bridging between two routers over a

serial interface (s0). Bridging will occur between the two Ethernet Inter-

faces on Router A (e0 and e1) and the two Ethernet Interfaces on Router

B (e0 and e1).

Figure 2. Transparent bridging between two routers over a serial interface

4.0 CONFIGURATION

The Model 2701/I features conﬁguration capability via hardware DIP

switches. This section describes all possible DIP switch conﬁgurations of

the Model 2701/I.

4.1 DIP SWITCH CONFIGURATION

The Model 2701/I has two sets of internal DIP switches that allow conﬁg-

uration for a wide range of applications. The sets of switches are

accessed from the underside. Figure 3 shows the location of the DIP

switches on the bottom of the printed circuit board.

Figure 3. Underside of Model 2701/I, Showing Location of DIP Switches

The Model 2701/I DIP switches (Switch Sets 1-2) can be conﬁgured as

either “ON” or “OFF”. Figure 4 shows the orientation of the DIP switches

with respect to ON/OFF positions.

Figure 4. Close up of conﬁguration switches

Switch SW1

A detailed description of each switch (SW1-1 through SW1-5) setting fol-

lows the summary table below:

Switch SW-1 through SW1-5. Use Switches SW1-5 to set the DTE

data rate.

SW1 SW2 SW3 SW4 SW5

Speed

Off

64 kbps

128 kbps

192 kbps

256 kbps

320 kbps

384 kbps

448 kbps

512 kbps

576 kbps

640 kbps

704 kbps

768 kbps

832 kbps

896 kbps

960 kbps

1024 kbps

1088 kbps

1152 kbps

1216 kbps

1280 kbps

1344 kbps

SW1 SW2 SW3 SW4 SW5

Speed

Off

1408 kbps

1472 kbps

1536 kbps

1600 kbps

1664 kbps

1728 kbps

1792 kbps

1856 kbps

1920 kbps

1984 kbps

Clear Channel 2048 kbps

Note When the data rate is set to 2.048Mb/s, the unit is forced into

G.703 mode, and it transmits user data on all 32 time-lots.There

is no framing information; therefore, the CRC4 MF (SW2-2)

switch is ignored. In all other rate settings, the unit employs

G.704 framing; TS0 is reserved for signaling.

SW1-6

SW1-7

Clock Mode

Off

Network (Received Recovered)

Internal

Network (Received Recovered)

SW1-6 and SW1-7 Clock Modes.

Network Clock—Transmitter timing is derived using the received line

signal (received recovered) from the network.

Internal Clock—Transmitter timing is derived from an internal clock

source.

Switch SW2

A detailed description of each switch (SW1-1 through SW1-5) setting fol-

lows the summary table below:

Switch SW2-1 Line Coding: HDB3 (default).

Use Switch SW2-1 to control the Network Line Coding options. Set

these options to be the same as the Line Coding given to you by your

Service Provider. If you are using two Model 2701/Is together as short

range modems, set both units to HDB3.

SW2-1 Line Encoding

Off

HDB3

AMI

Options: HDB3, AMI

HDB3 In this line coding, the transmitter substitutes a deliberate bipo-

lar violation when excessive zeros in the data stream are

detected. The receiver recognizes these special violations and

decodes them as zeros. This method enables the network to

meet minimum pulse density requirements. Unless AMI is

required in your application, HDB3 should be used whenever

possible.

AMI

Alternate Mark Inversion deﬁnes a pulse as a “mark,” a binary

one, as opposed to a zero. In an E1 network connection, signals

are transmitted as a sequence of ones and zeros. Ones are

sent as pulses, and zeros are sent as spaces, i.e., no pulse.

Every other pulse is inverted from the previous pulse in polarity,

so that the signal can be effectively transmitted. This means,

however, that a long sequence of zeros in the data stream will

cause problems, since the NTU receiving the signal relies on

the signal to recover the 2.048 Mb/s clock.

If you must use AMI, you should ensure that the data terminal

equipment connected to the unit provides a minimally accept-

able pulse density. For this reason, there are advantages to

using HDB3 instead. AMI coding does not inherently account for

ones density. To meet this requirement, the user should ensure

that the data inherently meets pulse density requirements.

Switch SW2-2: CRC-4 Multiframe.

In framed mode, SW2-2 is used for CRC-4 MF. When CRC-4 is enabled,

the unit monitors the incoming data stream for CRC-4 errors. It transmits

CRC-4 error counts to the transmitting unit. When using timeslot zero

(TS0), excessive errors may cause loss of frame or loss of sync. If CRC-

4 MF is used, both units must be set for set for CRC-4 MF. Otherwise, the

one using CRC-4 MF will detect loss of sync.

SW2-2

Off

Option

CRC-4 Disabled

CRC-4 Enabled

Note When the data rate is set to 2.048Mb/s, then the unit is forced

into G.703 mode, and it transmits user data on all 32 time-lots.

There is no framing information; therefore, the CRC4 MF (SW2-

2) switch is ignored. In all other rate settings, the unit employs

G.704 framing; TS0 is reserved for signaling.

Switch SW2-3 Data Inversion.

Set Switch S2-3 to determine whether or not the data stream from the

local DTE is inverted within the Model 2701 before being passed to the

G.703/G.704 network. An inverted data stream may be required when

you use the Model 2701 to communicate with a G.703 device (that

inverts the data) on the remote end. In typical installations, data inversion

is not necessary.

SW2-3

Option

Data not inverted

Data inverted

Off

Switch SW2-4: Remote Digital Loopback Type.

The user can set this switch to select the type of remote loop that will be

initiated by the Model 2701. If set to V.54, the Model 2701 will initiate a

V.54 loop when Remote Loop is selected by the front panel switches. If

set to CSU, the Model 2701 will initiate a CSU loop when Remote Loop

is selected by the front panel switches.

S2-4

Off

RDL Type

Initiate a V.54 RDL loop when selected

Initiate a CSU loopback when selected

Switch SW2-5 Front Panel Switches.

As the Front Panel Switches may be inadvertently toggled, or in the

event that the end-user may not need to use the switches, the installer

may disable the front panel switches. Set Switch S2-5 to determine

whether the front-panel toggle switches are active or inactive.

SW2-5

Off

Option

Front Panel Switches Enabled

Front Panel Switches Disabled

Switch SW2-6: V.54 Response Disabled (default).

V.54 Response is a special in-band loopback facility that sends a

pseudo-random pattern over the data stream. This is the only loopback

that the unit can initiate. This is useful for campus applications when you

need to put a remote unit in loopback.The unit responds to the V.54 loop-

back command, and the whole process takes only a few seconds to com-

plete. When V.54 Loopback is disabled, the unit will not be able to send

or respond to V.54 loopback commands. The duration of the loopback is

limited by the loopback timeout setting.

SW2-6

Off

Option

V.54 Response Enabled

V.54 Response Disabled

5.0 INSTALLATION

The Interconnecting cables shall be acceptable for

external use and shall be rated for the proper applica-

tion with respect to voltage, current, anticipated tem-

perature, ﬂammability, and mechanical serviceability.

WARNING

Once the Model 2701/I is properly conﬁgured, it is ready to connect to

the G.703/G.704 interface, to the Ethernet port, and to the power source.

This section describes how to make these connections.

5.1 CONNECTING TO THE G.703 NETWORK

The Power, G.703/G.704 and Ethernet Line connections are located on

the rear panel of the Model 2701/I. Figure 5 shows the location of each

of these ports.

Figure 5. Model 2701/I Rear Panel

Connecting Dual Coaxial Cable (75 ohm) to the G.703 Network

The Model 2701/I is equipped with dual female BNCs (TX and RX) for

connection to a 75 ohm dual coax G.703 network interface. If your

G.703/G.704 network terminates via dual coaxial cable, use the diagram

below to make the proper connections. See Figure 6 below.

Figure 6. Rear Panel, Showing Location of Connectors.

Note The outer conductor of the coax cables are isolated from system

earth ground.

When using the 75 Ohm interface, jumper straps JP2, JP6, and JP7

must be installed over the jumpers. The jumpers are located next to the

BNC connectors. Refer to the following section to open the case.

Opening the Case

Open the case by inserting a screwdriver into the slots and twist the

screwdriver head slightly. The top half of the case will separate from the

lower half of the case. Take caution not to damage any of the PC board

mounted components.

Connecting the Twisted Pair (120 ohm) to the G.703 Network

The Model 2701/I is equipped with a single RJ-48C jack for connections

to a 120 ohm twisted pair G.703/G.704 network interface. If your G.703/

G.704 network terminates via RJ-48C, use the connection diagram

(Figure 7) following the pinout and signals chart below to connect the

120 ohm G.703/G.704 network channel.

RJ-48C Jack

Signal Name

(RX) Receive (Ring)

(RX) Receive (Tip)

Shield

(TX) Transmit (Ring)

(TX) Transmit (Tip)

Shield

No connection

Figure 7. G.703/G.704 170 ohm Connection.

5.2 CONNECTING THE 10BASE-T ETHERNET PORT TO A PC

(DTE)

Figure 8. Connecting the 10Base-T Ethernet Port to a PC

The 10Base-T interface is conﬁgured as DTE (Data Terminal Equip-

ment). If the Model 2701/I is to to connect to another DTE device such

as a 10Base-T network interface card, construct a 10Base-T crossover

cable and connect the wires as shown in the diagram below (Figure 9).

Figure 9. 10Base-T Cross-over Cable Connection

5.3 CONNECTING THE 10BASE-T ETHERNET PORT TO A HUB

The 10Base-T interface is conﬁgured as DTE (Data Terminal Equip-

ment), just like a 10Base-T network interface card in a PC. Therefore, it

“expects” to connect to a 10Base-T Hub using a straight-through RJ-45

cable. Use the diagram below (Figure 10) to construct a cable to con-

nect the 10 BaseT interface to a 10Base-T Hub.

Figure 10. Connecting the 10Base-T Ethernet Port to a Hub

5.4 POWER CONNECTION

Universal AC Power (100–240 VAC)

The Model 2701/I uses a 5VDC, 2A universal input 100-240VAC, power

supply (center pin is +5V). The universal input power supply has a male

IEC-320 power entry connector. This power supply connects to the

Model 2701/I by means of a barrel jack on the rear panel. Many interna-

tional power cords are available for the universal power supply.

The Model 2701/I powers up as soon as it is plugged into an AC outlet--

there is no power switch..

DC Power

The 36-60 VDC DC to DC adapter is supplied with the DC version of the

Model 2701/I. The black and red leads plug into a DC source (nominal

48VDC) and the barrel power connector plugs into the barrel power sup-

ply jack on the 2701/I. (See Figure 11).

To Power

To -48VDC

Supply Jack

Source

-Vin

Black lead (-V)

Red lead (+V)

+Vin

Barrel power connector

Figure 11. Connecting DC Power to the 2701 DC Power Supply.

There are no user-serviceable parts in the

power supply section of the Model 2701. Con-

tact Patton Electronics Technical support at

(301)975-1007, via our web site at http://

WARNING

www.patton.com, or by e-mail at support@pat-

ton.com, for more information.

6.0 OPERATION

When the Model 2701/I has been properly conﬁgured and installed, it

should operate transparently. This sections describes power-up, LED

status monitors, and the built-in loopback test modes.

6.1 POWER-UP

Before applying power to the Model 2701/I, please read section 5.4,

“Power Connection” on page 20 and ensure that the unit is properly con-

nected to the appropriate power source..

6.2 LED STATUS MONITORS

The Model 2701/I features six front panel LEDs that monitor connections

on the G.703/G.704 and 10BaseT links, signaling, error and test modes.

Figure 10 (below) shows the front panel location of each LED. Descrip-

tions of each LED follow Figure 12.

Figure 12. 2701/I Front Panels

E1 Link

(Active Green) Solid green (On) indicates that the end to end E1

Link is up, signifying that the link is active. The E1 Link LED is

Off when the link is down.

10BT Link(Active Green)

Solid green indicates that the 10BaseT Ethernet interface has

detected a valid SQE heartbeat, signifying a valid 10BaseT

connection.

Status

Blinks yellow from one to eleven times to indicate system sta-

tus. Each pulse pattern is separated by a 2 second “off”

period. Greater pulse patterns have higher priority (buffer sat-

uration has greater priority than an empty MAC table). Valid

system statuses are:

1 pulse = system status is okay

2 pulses = no MAC entries in the MAC Address Table

3 pulses = Clear to Send (CTS) or Carrier Detect (DCD) from

base unit are not asserted

4 pulses = IM1/I buffer is saturated

5 pulses = WAN receive frame(s) too large

6 pulses = WAN receive frame(s) not octet aligned

7 pulses = WAN receive frame(s) aborted

8 pulses = Detected WAN receive frame(s) with CRC

9 pulses = Detected LAN receive frame(s) too large

10 pulses = Detected LAN receive frame(s) not octet aligned

11 pulses = Detected LAN receive frame(s) with bad CRC

LOS

The Loss of Sync LED lights when the unit loses synchroniza-

tion with the incoming signal. This may happen when there is a

framing mismatch or a loss of signal. In unframed mode, the

LOS LED monitors the status of the transmit clock.

(Active Yellow) Solid Yellow indicates an Active Test Mode. The

unit may be placed in test mode by the local user or by the

remote user

The error LED indicates various error conditions, including fram-

ing bit errors, excessive zeros, controlled slips, severe errors, or

bit errors (when sending V.52 test patterns). When sending a

test pattern, the LED will remain lit if the unit does not receive

the identical pattern. When it receives the correct pattern, the

LED will turn off. If error insertion is on, the LED will blink once a

second if everything is operating properly.

6.3 LOOP (V.54 & TELCO) DIAGNOSTICS

The Model 2701/I offers three V.54 loop diagnostics. Use these diagnos-

tics to test the NTU and any communication links. These tests can be

activated via the front panel switches.

Operating Local Loopback (LL)

The Local Loopback (LL) test checks the operation of the local Model

2701/I, and is performed separately on each unit.

Figure 13. Local Loopback for a Network Termination Application

To perform a LL test, follow these steps:

1. Activate LL. This may be done by selecting local loop on the front

panel switch.

2. .Perform a V.52 BER (bit error rate) test as described on page 25. 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 ter-

minal and the Model 2701/I.

Operating Remote Digital Loopback (RL)

The Remote Digital Loopback (RL) test checks the performance of both

the local and remote NetLink-E1™, as well as the communication link

between them. Any characters sent to the remote NetLink-E1™ in this

test mode will be returned back to the originating device.

Figure 14. Remote Loop in a Network Extension Application

There are two Remote Loops that can be initiated from the NetLink 2701/

I unit: (1) V.54 Loop, and; (2) CSU Loop. The user can select the type of

loop that can be initiated by Switch S2-4. When a loopback is initiated

this is the type of loop that the unit uses to loop up the remote unit and

which type of loop the unit will respond to.

To perform an RDL test, follow these steps:

1. Activate RDL. This may be done by setting the front panel switch to

‘Remote’.

2. Perform a bit error rate test (BERT) using the internal V.52 genera-

tor (as described on page 25), or using a separate BER Tester. If

the BER test indicates a fault, and the Local Line Loopback test

was successful for both NetLink™s, you may have a problem with

the twisted pair line connection.

CSU Loop

Although CSU Loop is predominantly a T1 function, the NetLink-2701/I

responds to central ofﬁce initiated loop commands. Customers can use

this facility when the Central Ofﬁce network switch supports CSU loops

over an E1 interface.

When CSU Loop is selected, and when in D4 framing mode, the NetLink

2701/I will implement the “loop up” command when it recognizes the pat-

tern “10000” in the data stream for a minimum of 5 seconds. The “loop

down” command is implemented by the pattern “100” in the data stream

for a minimum of 5 seconds.

The NetLink 2701/I will respond to Universal Loopback De-activate to

clear all central ofﬁce loops.

Using the V.52 (BER) Test Pattern Generator

To use the V.52 BER tests in conjunction with the Remote Digital Loop-

back tests (or with Local Line Loopback tests), follow these instructions:

1. Locate the “511/511E” toggle switch on the front panel of the 2701/I

and move it UP. This activates the V.52 BER test mode and trans-

mits a “511” test pattern into the loop. If any errors are present, the

local modem’s red “ER” LED will blink sporadically.

2. If the above test indicates no errors are present, move the V.52 tog-

gle switch DOWN, activating the “511/E” test with errors present. If

the test is working properly, the local modem's red “ER” LED will

blink once per second. A successful “511/E” test will conﬁrm that

the link is in place, and that the Model 2701/I’s built-in “511” genera-

tor and detector are working properly.

Note The above V.52 BER tests can be used independently of the

Remote Digital Loopback tests. This requires two operators:

one to initiate and monitor the tests at the local Model 2701/I,

and one to do the same at the remote Model 2701/I. In this

case, the test pattern sent by each Model 2701/I will not be

looped back, but will be transmitted down the line to the other

Model 2701/I. While one operator initiates test, the other moni-

tors for errors.

APPENDIX A

SPECIFICATIONS

A.1 NETWORK DATA RATE

2.048 Mbps

A.2 NETWORK CONNECTOR

RJ-48C/Dual Coax BNC

A.3 NOMINAL IMPEDANCE

75/120 ohm

A.4 LINE CODING

Selectable AMI or HDB3

A.5 LINE FRAMING

G.703 (Unframed) or G.704/G.732 (Framed)

A.6 CRC-4 MULTIFRAMING

Selectable On or Off

A.7 CLOCKING

Internal or Network (Receive Recover)

A.8 TIME SLOT RATE

64 kbps

A.9 NETWORK DATA RATES

64, 128, 192, 256, 320,384, 448, 512, 576, 640, 704, 768, 832, 896, 960,

1024, 1088, 1152, 1216, 1280, 1344, 1408, 1472, 1536, 1600, 1664,

1728, 1792, 1856, 1920, 1984, 2048 kbps

A.10 DISTANCE

Maximum 1.6 km (5,250 ft.) on 24 AWG Cable

A.11 POWER SUPPLY

+5 VDC External power supply/100–240 VAC, 50–60Hz, 0.4A

A.12 HUMIDITY

Up to 90% non-condensing

A.13 TEMPERATURE

0 to 50°C (32 to 122°F)

A.14 DIMENSIONS

Plastic Case – 9.0L x 5.3W x 2.0H cm (3.5L x 2.1W x 0.78H in.)

Metal Case – 3.2L x 13.8W x 14.6H cm (1.25L x 5.43W x 5.75H in)

APPENDIX B

ETHERNET 10BASE-T SPECIFICATIONS

B.1 DTE INTERFACE

10Base-T on RJ-45F

B.2 DTE DATA RATES

10Mbps

B.3 LAN CONNECTION

RJ-45, 10Base-T, 802.3 Ethernet

B.4 PROTOCOL

PPP (RFC 1661) with Bridging Control (RFC 1638)

B.5 MAC ADDRESS TABLE SIZE

4096 entries

B.6 MAC ADDRESS AGING

MAC addresses deleted after 8 minutes of inactivity

B.7 FRAME BUFFER

512 Frames

B.8 FRAME LATENCY

1 frame

B.9 DIAGNOSTICS

6V.54 Loopback; CSU Loopback; V.52 Patterns: 511

B.10 INDICATORS

E-1 Link, 10Base-T Link, Ethernet Status, Loss of Frame Sync, Error,

Test Mode

B.11 CONFIGURATION

Two 8-Position DIP Switches

APPENDIX C

FACTORY REPLACEMENT PARTS AND ACCESSORIES

Patton Model #

Description

2701/B

G.703/G.704 NTU with RS-530 interface

G.703/G.704 NTU with a V.35 interface

G.703/G.704 NTU with an X.21 interface

G.703/G.704 NTU w/ 10Base-T EN interface

Universal Input Power Supply

2701/C

2701/D

2701/I

08055DCUI

07M2701

User Manual

.NOTES

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.NOTES

_______________________________________________________

NOTES

_______________________________________________________

Patton Electronics Company

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