ZyXEL Communications GS1100 Series User manual

Quick Start Guide
www.zyxel.com
GS1 1 0 0 Series
Unm anaged Gigabit Ethernet Switch
Version 1.00
Edition 3, 06/ 2012
Copyright © 2012 ZyXEL Comm unications Corporation
User’s Guide

GS1100 Series User’s Guide2
IMPORTANT!
READ CAREFULLY BEFORE USE.
KEEP THIS GUIDE FOR FUTURE REFERENCE.
Screenshots and graphics in this book may differ slightly from your product due to differences in
your product firm ware or your com puter operating system. Every effort has been made to ensure
that the inform ation in this m anual is accurate.

Table of Contents
GS1100 Series User’s Guide 3
Table of Contents
Table of Contents .................................................................................................................................3
Chapter 1
Getting to Know Your Switch...............................................................................................................5
1.1 Introduction .........................................................................................................................................5
1.2 Features ..............................................................................................................................................6
1.3 Applications .........................................................................................................................................6
1.3.1 Standalone Workgroup ..............................................................................................................6
1.3.2 Bridging .....................................................................................................................................7
1.4 Power Over Ethernet (PoE) ................................................................................................................7
Chapter 2
Hardware Description and Connection ..............................................................................................9
2.1 Rear Panel .......................................................................................................................................9
2.1.1 Rear Panel Power Connection ..................................................................................................9
2.2 Front Panel ..........................................................................................................................................9
2.2.1 RJ-45 Auto-negotiating Ports ..................................................................................................10
2.2.2 IEEE 802.3az EEE ..................................................................................................................10
2.2.3 Mini-GBIC Slots (GS1100-24 Only) .........................................................................................10
2.2.4 Front Panel Connections .........................................................................................................12
2.2.5 Front Panel LEDs ....................................................................................................................12
2.3 Hardware Installation ........................................................................................................................13
2.3.1 Wall Mounting ..........................................................................................................................14
2.3.2 Rack Mounting .........................................................................................................................14
2.3.3 Mounting the Switch on a Rack ...............................................................................................15
Chapter 3
Troubleshooting..................................................................................................................................17
3.1 Improper Network Cabling and Topology ..........................................................................................18
Appendix A Legal Information............................................................................................................19
Index ....................................................................................................................................................21

Table of Contents
GS1100 Series User’s Guide
4

GS1100 Series User’s Guide 5
CHAPTER 1
Getting to Know Your Switch
1.1 Introduction
This chapter describes the key features, benefits and applications of your Switch.
This User’s Guide covers the following m odels: GS1100-8HP, GS1100-16, and GS1100-24. The
Switch is a 10/ 100/ 1000 Mbps multi-port switch that can be used to build high-perform ance
switched workgroup networks. The Switch is a store-and-forward device that offers low latency for
high-speed networking. The Switch is designed for workgroups, departm ents or backbone
computing environm ents for sm all businesses.
The GS1100-8HP has four GbE PoE ports that can supply power to the connected PoE powered
devices.
The GS1100-24 has two mini-GBIC ports for uplink connection. Use m ini-GBIC transceivers in these
slots for connections t o backbone Ethernet switches.
The Switch has a built-in algorithm that autom atically assigns priority to received packets. It can
operate in low power idle m ode in com pliance with I EEE 802.3az Energy Efficient Ethernet (EEE).
Table 1 GS1100 Series Comparison Table
PORT/SWITCH DETAILS GS1100-8HP GS1100-16 GS1100-24
8 10/ 100/ 1000Base-T Ethernet ports
(including 4 PoE ports)
16 10/ 100/ 1000Base-T Ethernet ports
24 10/ 100/ 1000Base-T Ethernet ports
2 m ini- GBI C ( SFP) slot s
One physical IEEE 802.3az ON/ OFF button
One power ON/ OFF switch

Chapter 1 Getting to Know Your Switch
GS1100 Series User’s Guide
6
Figure 1 Front Panel
1.2 Features
The following are the essential features of the Switch.
• Conform s to IEEE 802.3, 802.3u, 802.3ab and 802.3x standards.
• Auto- negotiating 10/ 100/ 1000 Mbps Gigabit Ethernet (GbE) RJ-45 ports.
• Auto- sensing crossover for all 10/ 100/ 1000 Mbps Gigabit Ethernet (GbE) RJ-45 ports.
• Supports N-Way protocol for speed (10/ 100/ 1000 Mbps) and duplex mode (Half/ Full) auto-
detection.
• Supports store-and-forward switching.
• Supports autom atic address learning.
• Supports IEEE 802.3az EEE
• Support I EEE 802.3af and IEEE 802.3at PoE standards (only GS1100-8HP)
• Full wire speed forwarding rate.
• Supports 802.1p CoS.
• Embedded 8K MAC address table providing 8000 MAC addresses entries.
1.3 Applications
This section provides two network topology examples in which the Switch is used.
1.3.1 Standalone Workgroup
In this application, the Switch is an ideal solution for sm all networks where rapid growth can be
expected in the near future.
GS1100-8HP
GS1100-16
GS1100-24

Chapter 1 Getting to Know Your Switch
GS1100 Series User’s Guide 7
The Switch can be used standalone for a group of heavy traffic users. You can connect com puters
directly to the Switch’s port or connect other switches to the Swit ch.
In this example, all com puters can share high-speed applications on the server. To expand the
network, simply add more networking devices such as switches, routers, computers, print servers
etc.
Figure 2 Standalone Workgroup Exam ple
1.3.2 Bridging
With its large address table and high perform ance, the Switch is an ideal solution for departm ent
networks to connect to the corporate backbone or for connecting network segm ents.
The following figure depicts a typical segm ent bridge application of the Switch in an enterprise
environm ent. The two networks (RD and Sales), the standalone server and the computers can all
comm unicate with each other and share all network resources.
Figure 3 Bridging Exam ple
1.4 Power Over Ethernet (PoE)
The PoE function is available for GS1100-8HP only.
Ports 1 to 4 on the GS1100-8HP are I EEE 802.3at High Power over Ethernet (PoE) com pliant and
can supply power of up to 30W per Ethernet port.
A powered device (PD) is a device such as an access point or a switch, that supports PoE (Power
over Ethernet) so that it can receive power from another device through a 10/ 100/ 1000 Mbps
Ethernet port.

Chapter 1 Getting to Know Your Switch
GS1100 Series User’s Guide
8
In the figure below, the I P camera and IP phone get their power directly from the Switch. Aside
from minim izing the need for cables and wires, PoE rem oves the hassle of trying to find a nearby
electric outlet to power up devices.
Figure 4 Powered Device Exam ples

GS1100 Series User’s Guide 9
CHAPTER 2
Hardware Description and Connection
2.1 Rear Panel
The three-pronged power receptacle is located on the rear panel of the Switch. Refer to the power
supply requirem ents on the panel.
Figure 5 Rear Panel
2.1.1 Rear Panel Power Connection
Connect one end of the supplied power cord to the power receptacle on the back of the Switch and
the other end to the appropriate power source.
For the GS1100-8HP and GS1100- 16, use the POW ER ON / OFF switch to have the Switch power
on or off.
2.2 Front Panel
The front panel of the Switch includes the auto- negotiating 10 Base-T/ 100 Base-TX/ 1000 Base-T
RJ-45 ports and the LEDs.
The GS1100-24 has two m ini-GBIC ports. Refer to Section 2.2.3 on page 10 for more inform ation.
GS1100-16
GS1100-24
GS1100-8HP

Chapter 2 Hardware Description and Connection
GS1100 Series User’s Guide
10
2.2.1 RJ-45 Auto-negotiating Ports
The 10 Base-T/ 100 Base-TX/ 1000 Base-T RJ-45 ports are auto- negotiating and auto- crossover.
An auto-negotiating port can detect and adjust to the optimum Ethernet speed (10/ 100/ 1000
Mpbs) and duplex mode (full duplex or half duplex) of the connected device.
An auto-crossover (auto-MDI/ MDI-X) port automatically works with a straight-through or crossover
Ethernet cable.
2.2.2 IEEE 802.3az EEE
The Switch supports the I EEE 802.3az EEE (Energy Efficient Ethernet) standard to help reduce
power consumption. This allows the Switch to go into power saving mode and switch off part of
receive and transm it circuitry when it is not transm itting or receiving data through an Ethernet
connection.
An EEE-enabled device initiates Low Power Idle (LPI) signals to negotiate and wake up the rem ote
device when there is data to be transm itted. To use EEE, both devices should be EEE com pliant.
EEE is configured on a per-system basis in the Switch. I f one of the networking devices that
connect to the Switch doesn't support EEE, EEE m ay not work in the Switch to save power.
The EEE feature is enabled by default on the GS1100-16 and GS1100-24. Press in the I EEE
8 0 2 .3 a z EEE ON / OFF button on the GS1100-8HP front panel to turn on the EEE feature. Disable it
if the rem ote side doesn't support it or you don't want the network perform ance to be im pacted due
to the latency from the additional time required for the sleep and wake transition.
2.2.3 Mini-GBIC Slots (GS1100-24 Only)
These are slots for m ini- GBIC (Gigabit I nterface Converter) transceivers. A transceiver is a single
unit that houses a transm itter and a receiver. The Switch does not com e with transceivers. You
must use transceivers that comply with the Small Form-factor Pluggable (SFP) Transceiver
MultiSource Agreement ( MSA). See the SFF com m ittee’s I NF-8074i specification Rev 1.0 for details.
You can change transceivers while the Switch is operating. You can use different transceivers to
connect to Ethernet switches with different types of fiber-optic or even copper cable connectors.
To avoid possible eye injury, do not look into an operating fiber-optic
module’s connectors.
• Type: SFP connection interface
• Connection speed: 1 Gigabit per second (Gbps)
2.2.3.1 Transceiver Installation
Use the following steps to install a mini-GBI C transceiver (SFP m odule).
1Insert the transceiver into the slot with the exposed section of PCB board facing down.
2Press the transceiver firm ly until it clicks into place.

Chapter 2 Hardware Description and Connection
GS1100 Series User’s Guide 11
3The Switch autom atically detects the installed transceiver. Check the LEDs to verify that it is
functioning properly.
4Close the transceiver’s latch (latch styles vary).
5Connect the fiber optic cables to the transceiver.
Figure 6 Transceiver Installation Exam ple
Figure 7 Connecting the Fiber Optic Cables
2.2.3.2 Transceiver Removal
Use the following steps to rem ove a mini-GBIC transceiver (SFP module).
1Remove the fiber optic cables from the transceiver.
2Open the transceiver’s latch (latch styles vary).
3Pull the transceiver out of the slot.
Figure 8 Rem oving the Fiber Optic Cables
Figure 9 Opening the Transceiver’s Latch Exam ple
Figure 10 Transceiver Rem oval Exam ple

Chapter 2 Hardware Description and Connection
GS1100 Series User’s Guide
12
2.2.4 Front Panel Connections
You can use unshielded twisted pair (UTP) or shielded twisted- pair (STP) Ethernet cables for RJ-45
ports. The following table describes the types of network cable used for the different connection
speeds. .
You can use either crossover or straight- through cables for all the ports.
2.2.5 Front Panel LEDs
The LED I ndicators give real-time inform ation about the status of the Switch. The following table
provides descriptions of the LEDs.
Figure 11 Front Panel LEDs
Table 2 Network Cable Types
SPEED NETWORK CABLE TYPE
10 Mbps Category 3, 4 or 5 UTP/ STP
100 Mbps Category 5 UTP/ STP
1000 Mbps Category 5e, 6 UTP/ STP
GS1100-8HP
GS1100-16
GS1100-24

Chapter 2 Hardware Description and Connection
GS1100 Series User’s Guide 13
The following table describes the LEDs.
2.3 Hardware Installation
See the following table for a com parison of the hardware installation m ethods of each GS1100
model:
Table 4 GS1100 Series Installation Comparison Table
Note: Ask an authorized technician to attach the Switch to the rack/ wall.
For GS1100-8HP and GS1100-16, you can place the Switch directly on top of your desk or have it
wall-m ounted. For GS1100-16 and GS110-24, the size is suitable for rack-mounting and you can
refer to Section 2.3.2 on page 14 for instruction. Take note of the following:
• The Switch should have a minim um 25 m m space around it for ventilation.
• The Switch should be placed in a desk that has a level surface and that is able to support the
weight of the Switch.
To start using it, sim ply connect the power cables and turn on the Switch.
Table 3 The Front Panel LED Descriptions
LED COLOR STATUS DESCRIPTION
PWR Green On The Switch is on and receiving power.
Off The Switch is not receiving power.
PoE MAX Red On Power supplied to the PoE port(s) reachs the power budget limit or
exceeds t he total PoE power budget on the Switch.
Off Power supplied to the PoE port(s) is below the power budget limit.
PoE Am ber On Power is supplied to the PoE port.
Off Power is not supplied to the PoE port.
LINK/
ACT
Green On The port is connected to an Ethernet net work.
Blinking The port is receiving or transm itt ing data.
Off The port is not connected to an Ethernet network.
1G
10/ 100
Green On The port is connected to an Ethernet network at 1000M speed.
Blinking The port is receiving or transmitting data at 1000M speed.
Am ber On The port is connected to an Ethernet network at 10M or 100M speed.
Blinking The port is receiving or transm itting data at 10M or 100M speed.
Off The port is not connected to an Ethernet network.
MODEL FEATURE GS1100-8HP GS1100-16 GS1100-24
Desktop Device
Wall - m ou nt able
Rack- m ount able

Chapter 2 Hardware Description and Connection
GS1100 Series User’s Guide
14
2.3.1 Wall Mounting
Do the following to attach your Switch to a wall.
See Table 5 on page 14 for how far apart to place the screws.
1Screw the two screws provided with your Switch into the wall (see the figure in step 2). Use screws
with 6 m m ~ 8 m m (0.24" ~ 0.31") wide heads. Do not screw the screws all the way in to the wall;
leave a small gap between the head of the screw and the wall.
The gap m ust be big enough for the screw heads to slide into the screw slots and the connection
cables to run down the back of the Switch.
Note: Make sure the screws are securely fixed to the wall and strong enough to hold the
weight of the Switch with the connection cables.
2Align the holes on the back of the Switch with the screws on the wall. Hang the Switch on the
screws.
The Switch should be wall-mounted horizontally. The Switch's side
panels with ventilation slots should not be facing up or down as this
position is less safe.
2.3.2 Rack Mounting
The Switch can be mounted on an EIA standard size, 19-inch rack or in a wiring closet with other
equipm ent. Follow the steps below to m ount your Switch on a standard EIA rack using a rack-
mounting kit.
Table 5 Distance between the centers of the holes for wall mounting
MODEL DISTANCE
GS1100-8HP 120 m m
GS1100-16 150 mm

Chapter 2 Hardware Description and Connection
GS1100 Series User’s Guide 15
Rack-mounted Installation Requirements
• Two m ounting brackets.
• Eight M3 flat head screws and a # 2 Philips screwdriver.
• Four M5 flat head screws and a # 2 Philips screwdriver.
Failure to use the proper screws may damage the unit.
Precautions
• Make sure the rack will safely support the com bined weight of all the equipm ent it contains.
• Make sure the position of the Switch does not m ake the rack unstable or top- heavy. Take all
necessary precautions to anchor the rack securely before installing the unit.
Attaching the Mounting Brackets to the Switch
1Position a mounting bracket on one side of the Switch, lining up the four screw holes on the bracket
with the screw holes on the side of the Switch.
Figure 12 Attaching the Mounting Brackets (GS1100- 16)
Figure 13 Attaching the Mounting Brackets (GS1100- 24)
2Using a # 2 Philips screwdriver, install the M3 flat head screws through the mounting bracket holes
into the Switch.
3Repeat steps 1and 2to install the second mounting bracket on the other side of the Switch.
4You m ay now m ount the Switch on a rack. Proceed to the next section.
2.3.3 Mounting the Switch on a Rack
1Position a mounting bracket (that is already attached to the Switch) on one side of the rack, lining
up the two screw holes on the bracket with the screw holes on the side of the rack.

Chapter 2 Hardware Description and Connection
GS1100 Series User’s Guide
16
Figure 14 Mounting the Switch on a Rack (GS1100-16)
Figure 15 Mounting the Switch on a Rack (GS1100-24)
2Using a # 2 Philips screwdriver, install the M5 flat head screws through the mounting bracket holes
into the rack.
3Repeat steps 1and 2to attach the second mounting bracket on the other side of the rack.

GS1100 Series User’s Guide 17
CHAPTER 3
Troubleshooting
This section describes com mon problem s you m ay encounter with the Switch and possible
solutions.
Troubleshoot the Switch using the LEDs to detect problems.
The PW R LED on the front panel does not light up.
• Check the connections from your Switch to the power source. Make sure you are using the
supplied power cord and that you are using an appropriate power source. Refer to the product
specifications.
• Make sure the power source is turned on and that the Switch is receiving sufficient power.
• I f these steps fail to correct the problem , contact your local distributor for assistance.
The LI N K/ ACT LED does not light up when a device is connected.
• Verify that the attached device( s) is turned on and properly connected to your Switch.
• Make sure the network adapters are working on the attached devices.
• Verify that proper network cable type is used and its length does not exceed 100 m eters. For
more inform ation on network cable types, see Section 3.1 on page 18.
The PWR LED is off and/ or power is not being supplied to my PoE-enabled device. (For
GS1100-8HP)
• Check to see that the power cord is securely connected to the GS1100- 8HP and an appropriate
power source. Make sure the power source is on and functioning properly.
• Check that the Ethernet cables are connected properly and that you are using the correct type of
Ethernet cable. Contact your local distributor if the problem persists.

Chapter 3 Troubleshooting
GS1100 Series User’s Guide
18
3.1 Improper Network Cabling and Topology
Im proper network cabling or topology setup is a comm on cause of poor network perform ance or
even network failure.
Figure 16 Troubleshooting Im proper Network Cabling and Topology
PROBLEM CORRECTIVE ACTION
Faulty cables Using faulty net work cables may affect data rates and have an im pact on your net work
perform ance. Replace with new standard network cables.
Non-standard
network cables
Non-standard cables may increase the number of network collisions and cause other
network problems that affect your network performance. Refer to Section 2.2.4 on page 12
for m ore inform ation on net work cable types.
Cabling Length If you use longer cables than are needed, transm ission quality m ay be affected.
The network cables should not be longer than the limit of 100 m eters.
Too m any hubs
between the
computers in
the network
Too m any hubs (or repeaters) between the connected com puters in the network m ay
increase the num ber of network collision or other network problem s. Rem ove unnecessary
hubs from the network.
A loop in the
data path
A dat a path loop for ms when t here is m ore t han one pat h or route bet ween two net work ed
computers. This results in broadcast storms that will severely affect your network
perform ance. Make sure there are no loops in your network topology.

GS1100 Series User’s Guide 19
APPENDIX A
Legal Information
Copyright
Copyright © 2012 by ZyXEL Com m unications Corporation.
Th e cont en t s of t h is p ublicat i on m ay n ot be r ep rod uced in any p ar t or as a w hol e, t r an scr ibed , st or ed in a r et r ieval sy st em , t ranslated into
any language, or transmitted in any form or by any m eans, elect ronic, mechanical, m agnetic, optical, chem ical, photocopying, manual, or
otherwise, without the prior writt en permission of ZyXEL Communications Corporation.
Published by ZyXEL Com m unications Corporation. All rights reserved.
Disclaimer
Zy XEL does not assum e any liabilit y arising out of the applicat ion or use of any products, or soft ware described herein. Neither does it
convey any license under its patent rights nor the patent rights of ot hers. ZyXEL further reserves t he right to m ake changes in any
products described herein without not ice. This publication is subject to change without notice.
Certifications
Federal Communications Commission (FCC) Interference Statement
This device com plies with Part 15 of FCC rules. Operation is subject to the following two conditions:
• This device may not cause harm ful interference.
• This device m ust accept any int erference received, including interference t hat m ay cause undesired operat ions.
FCC Warning
This device has been test ed and found to com ply wit h the limits for a Class A digital switch, pursuant to Part 15 of the FCC Rules. These
lim its are designed to provide reasonable protect ion against harm ful interference in a comm ercial environm ent . This device generat es,
uses, and can radiate radio frequency energy and, if not installed and used in accordance wit h the instruct ion m anual, m ay cause harmful
interfer ence t o radio com m unicat ions. Operat ion of t his device in a residential area is likely to cause harmful interference in which case
the user will be required to correct the int erference at his own expense.
CE Mark Warning:
This is a class A product . I n a dom est ic environm ent t his pr oduct m ay cause radio int er fer ence in which case t he user m ay be required t o
take adequate measures.
Taiwanese BSMI (Bureau of Standards, Metrology and Inspection) A Warning:
警告使用者
這是甲類的資訊產品，在居住的環境使用時，
可能造成射頻干擾，在這種情況下，
使用者會被要求採取某些適當的對策。
Notices
Changes or m odifications not expressly approved by the party responsible for com pliance could void the user's authority to operate the
equipm ent.
Cet appareil num érique de la classe A est conform e à la norm e NMB-003 du Canada.
CLASS 1 LASER PRODUCT
APPAREIL À LASER DE CLASS 1
PRODUCT COMPLI ES WI TH 21 CFR 1040 .10 AND 104 0.1 1.
PRODUI T CONFORME SELON 21 CFR 1040.10 ET 1040.11.
Viewing Certifications
Go to htt p: / / www.zyxel.com to view t his produ ct ’s docu m ent at ion and cert ificat ions.
ZyXEL Limited Warranty
ZyXEL warrants t o t he original end user ( purchaser) that t his product is free from any defects in material or workm anship for a specific
period (t he Warrant y Period) from t he dat e of purchase. The Warranty Period varies by region. Check with your vendor and/ or the
authorized ZyXEL local distributor for details about the Warranty Period of this product. During the warranty period, and upon proof of
purchase, should the product have indications of failure due to faulty workm anship and/ or m aterials, ZyXEL will, at it s discretion, repair or
replace the defective products or com ponents without charge for either part s or labor, and to whatever extent it shall deem necessary to
restore the product or components to proper operating condit ion. Any replacem ent will consist of a new or re- m anufactured functionally
equivalent product of equal or higher value, and will be solely at the discret ion of ZyXEL. This warranty shall not apply if the product has
been m odified, m isused, tampered with, dam aged by an act of God, or subjected t o abnorm al working conditions.

Appendix A Legal Information
GS1100 Series User’s Guide
20
Note
Repair or replacem ent, as provided under this warranty, is the exclusive rem edy of the purchaser. This warranty is in lieu of all ot her
warr ant ies, express or im plied, including any im plied warrant y of m erch ant abilit y or fit ness for a par ticu lar use or pu rpose. ZyXEL shall in
no event be held liable for indirect or consequential dam ages of any kind to t he purchaser.
To obtain the services of this warranty, contact your vendor. You m ay also refer to the warranty policy for the region in which you bought
the device at htt p: / / www.zyxel.com / web/ support _warranty_info.php.
Registration
Register your product online t o receive e- m ail notices of firmware upgrades and inform ation at www.zyxel.com for global products, or at
www.us.zyxel.com for North American products.
Safety Warnings
• Do NOT use t his product near water, for exam ple, in a wet basement or near a swim m ing pool.
• Do NOT expose your device t o dam pness, dust or corrosive liquids.
• Do NOT store things on the device.
• Do NOT install, use, or service this device during a thunderstorm. There is a rem ote risk of electric shock from lightning.
• Do not obstruct the device ventillation slot s as insufficient airflow m ay harm your device.
• Connect ONLY suitable accessories t o the device.
• Do NOT open the device or unit. Opening or rem oving covers can expose you to dangerous high voltage points or other risks. ONLY
qualified service personnel should service or disassem ble this device. Please contact your vendor for further information.
• Make sure to connect t he cables to the correct port s.
• Place connecting cables carefully so that no one w ill st ep on t hem or st um ble ov er t hem .
• Always disconnect all cables from this device before servicing or disassem bling.
• Use ONLY an appropriate power adaptor or cord for your device. Connect it t o the right supply voltage (for ex am ple, 110V AC in North
Am erica or 230V AC in Europe).
• Use ONLY power wires of the appropriate wire gauge for your device. Connect it to a power supply of the correct volt age.
• Do NOT allow anything to rest on the power adaptor or cord and do NOT place the product where anyone can walk on the power
adapt or or cord.
• Do NOT use t he device if t he power adaptor or cord is dam aged as it m ight cause electrocution.
• I f the power adaptor or cord is dam aged, rem ove it from t he device and the power source.
• Do NOT att empt to repair the power adaptor or cord. Contact your local vendor to order a new one.
• Fuse Warning! Replace a fuse only with a fuse of the sam e type and rating.
Your product is m arked with this sym bol, which is known as the WEEE m ark. WEEE stands for Waste Elect ronics and
Electrical Equipment. I t m eans that used electrical and electronic products should not be mixed with general waste. Used
electrical and electronic equipm ent should be t reated separately.