New York City College of Technology

Robotics & Intelligent Systems Laboratory


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EMT2455 Data Communications

Instructor: Dr. Li

Email: xhli@citytech.cuny.edu

Office Hours:  Thursday 1:30~2:30PM; Friday 2:30~5PM (Fall 2018)


Welcome to EMT2455 Data Communications, one of the fundamental courses to computer networks! The basic "secrets" behind communication systems, computer networks and the Internet will be revealed here. Have a quality and fun learning experience! This webpage can simply be reached by Googling "City Tech EMT2455 Dr. Li".


Course Description (from the latest College Catalog):

Fundamentals of data communications and computer networks protocols and standards. It provides a basic understanding of data communication systems with practical examples of communication networks as applied in engineering technology. Study of OSI and TCP/IP models, data transmissions, transmission media, bandwidth utilization, network topologies, network cabling system, IP addressing, TCP/IP suite, local area networks (LANs), wide area networks (WANs), wireless network, and network security. Students carry out experiments using modern hardware and software networking tools.


Grading Policy:
Attendance 10%
Quizzes 20%
Lab Reports 20%
Midterm Exam 20%
Final Exam & Extra Credits 30%

                      A: 93~100         A-: 90~92.99     B+: 87~89.99     B: 83~86.99
                      B-: 80~82.99     C+: 77~79.99    C: 70~76.99       D: 60~69.99 


Course Documents:

  Course Syllabus: Detailed information about the course and course policies, including pre-requisitives, textbook, grading policy, and other course policies.

  Labs & Lab Reports Requirements: Detailed requirements on lab experiments and lab reports (including report's content and format). Please thorough read it.

  Additional Guide on How to Write Technical Report: A very good guide written by IET (Institute of Engineering & Technology, the largest international non-for-profit engineering professional organization dated back to 1871). NEW!!


  Backbone of the Internet: Have you ever wondered how your home computer is connected to the Internet? Yes, it is connected to the DSL or cable modem provided by your ISP. But where the modem is connected to? (slides not available now).

  User Guide of the Crimp Tool: The pack and simple user guide that come with the crimp tool we used in the class.


Software Download Links:  NEW!!

  WireShark:   It is a free, and one of the most popular packet/protocol analyzer software. It supports Linux, OS X, BSD, Solaris, and Microsoft Windows.  https://www.wireshark.org/download.html

  Capsa Free by ColaSoft:  Free, but registration is required! Runs on Windows only.    http://www.colasoft.com/capsa-free/

  OPNET:   One of the most popular commercial computer networks modeling, simulation and performance management software. OPNET Modeler has an academic edition available:  https://enterprise37.opnet.com/4dcgi/SIGNUP_NewUserOther

  ns-2:   The very powerful and advanced network simulator widely used in research and high-ed teaching.  It is open-source. It runs on GNU/Linux, FreeBSD, Solaris, Mac OS X and Windows that support Cygwin. One needs to know scripting language, queuing theory and modelling techniques to use it.  ns-2 (build of 2009) is not actively maintained any more.

  ns-3:   Descendant of the very famous ns-2. Advanced and complex as ns-2, but unfortunately not backward compatible with ns-2.  Just like ns-2, ns-3 has no GUI and requires very considerable time to learn and use.   http://www.nsnam.org/

               ns-3's wiki page: https://www.nsnam.org/wiki/Main_Page


NYCCT WLAN Site Survey Experiment:  NEW!!

  Experiment Procedure & Handout:   See the lab handout provided by the instructor (also posted on the Blackboard).

  Floorplans of Namm Building: (Note: if there is any inconsistance betwn sector map and floorplan map, see the map of the correspoinding entire floor for accuracy!
GroundFL_SectorA 1stFL_SectorA 1stFL
2ndFL 2ndFL_SectorA 2ndFL_SectorB
3rdFL_SectorA 4thFL 4thFL_SectorB
4thFL_SectorC(Library 1level) 5thFL_SectorC(Library 2level)  

     Floorplans of Voorhees Building: Voorhees 6FL  1FL

Tentative Class Schedule:

      Note: Click available links (in red color) in the following table for lecture slides.

      Open Lab Hours: Thursday 11:30AM~2PM, V606/608, started from the 5th week






Intro to Course and course syllabus


2, 3rd

Ch 1.  Intro to Computer Networks and History of the Internet, OSI and TCP/IP models, packet switching, encapsulation



Ch 2-1. Network topology, multiplexing, transmission media, fiber optical communication, wireless communication, Structral Cabling System

Quiz 1;
Ch2-2. Internet backbone


Ch 2-3. Submarine Communications Cables Slides


Ch 2-4. Data and signal, Signal transimission, modulation, baseband & broadband, Nyquist theorem



Midterm Exam

Ch 3. Data Link Layer: Ethernet protocol, packet, MAC, etc



Ch 3. (contd.) Ethernet cables
Lab 1: Ethernet cabling



Quiz 2;
Lab 2:
Packet Analyzer



Ch 4.1. Network Layer: ARP;      

Lab 3: ARP  



Ch 4.2. IP Addressing    


  Lab4: WiFi
  Lab5: TCP, UDP (optional)
Lab handout posted on Blackboard  


Final Exam



Example Labs/Projects from Past Semesters:



Go Mobile!

You can simply use your smartphone or tablet to scan the following 2D barcode to access this webpage on the go.

EMT2455 URL QRCode


Follow me on Twitter for Course Annoucements:

As an instructor in computer engineering, I am determined to introduce the most up-to-date technologies and materials into the classroom. I am also determined to apply the most current or leading technology tools into the classroom, which reflects the state-of-the-art or trend of new computing and information technologies.

has and are being used by many leading universities as a new and proved effective tool for a better communication between instructor and students, and among the students. Through this course, I will use Twitter to promptly and smoothly send announcements, listen to your suggestion and address your concerns.

You can simply use your smartphone to scan the following 2D barcode to access my twitter. Follow me on twitter for any future annoucements, news and discussions regarding our class.

Prof. X Li's Twitter



    Summer Intern Opportunities:   Brooklyn Navy Yard had direct collaboration with our College and hired many of our City Tech students in the past as summer interns. The internship program in Brooklyn Navy Yard is open to accept applications until April 2. A variety of intern positions are offered by the companies inside Brooklyn Navy Yard. See flyer here. Check details by clicking the link:  https://brooklynnavyyard.org/employment/summer-internship/ NEW!!

    Open Lab is Available!  Please be advised that effective from the 5th Thursday of this semester, open lab will be avaiable in room V606, V608 and V613. You are welcome to use these lab rooms and equipments there to work on your projects or lab experiments. Open Lab hours are: Thursdays 11:20AM-2:00PM.

Archived Announcements:

     Brooklyn Tech Triangle U is back!  The Be.In Symposium (formerly known as "Brooklyn Tech Triangle U" is backin this April! It features a series of exciting events, panels, networking events that bring together the technology, digit media andeducation community from Downtown Brooklyn, DUMBO and BNY. See http://beinbrooklyn.org/symposium/ for details.

    NJ Tech Council IoT Conference 2017 on April 26, 2017:  The annual NJ Tech Council IoT Conference 2017 will feature AWS IoT cloud and AT&T foundry, Smart City, smart transportation, many IoT projects demo and networking reception. It will be hold at Steven Insititution of Technology, Hoboken, NJ, on April 26, 2017. If interested, please contact Dr. Li for free-registration promotion code by April 12. See the link here for detailed conference agenda.

    Brooklyn Tech Triangle Technology Company Tour  is scheduled on Friday, April 8, 2016. See the Blackboard for details.

    Good news: Schneider Electric is Hiring! Schneider Electric is one of the leading companies in the fields of energy managment and infrastruture equipments all over the global. It has several different openning, both full-time and part-time. They come to our campus to recruit. You are highly suggested to attend their info session on March 3, 2015, 1-2PM, at room N402. They will come back on March 19 for interviewing. Please see CET Dept. Secretary for more details! 

    Brooklyn Tech Triangle U: A series of events to connect the Tech+Arts+Academic communities in Brooklyn MetroTech, DUMBO and Brooklyn Navy Yard. Career events on March 5 and 6, 2015: http://brooklyntechtriangle.com/tech-u/#career-events

    MobileWeek NY 2015 Hiring Mixer: Join the official MobileWeek Hiring Mixer hosted at Yelp! Which is free for all developers and designers! Date: April 21, 2015, 5:30 PM 8:30 PM, Venue: YELP! Office NYC | 11 Madison Ave, 16th Floor, New York, NY 10010   See MobileWeek official website for details:   http://mobileweek.co/hiring/



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Last Update: March. 7, 2018