What are two basic concepts that define how signals are sent down a transmission media?
balanced and unbalanced
A/An _____________ interface makes the connection susceptible to noise, which limits data rate and maximum distance between the devices.
A/An ______________ interface can support higher data rates and a greater distance between devices with less interference.
The communication standard that specifies performance characteristics for unshielded twisted pair telecommunications cabling is _______________________________.
Which digital signal format has only one polarity with respect to zero and is either positive or negative?
Which digital signal format has two polarities, one positive and one negative?
Name the three most common types of digital timing methods.
Asynchronous, Synchronous and Isochronous Timing
In which timing method is each information character synchronized by the use of stop-and-start bits?
How is data transmitted in a synchronous method?
In synchronous timing, data is transmitted in continuous streams with reference to an external clock signal.
The ___________ refers to the amount of time a digital signal is left at a particular voltage level to indicate a value.
Bit Interval/Bit Time
___________ is equivalent to the maximum number or signaling elements (characters) sent per second.
What form is used to prepare a Telecommunications Request (TR) and who initiates the form?
AF-3215, initiated by the user
Who produces the Telecommunications Service Order (TSO)?
________________ is a circuit assignment used to determine the importance or precedence for provisioning (to install) or restoring telecommunications services.
Telecommunications Service Priorities (TSP)
What are the two parts of the TSP Authorization Code?
TSP Control Identifier and TSP Code
A multiplexer combines several channels into a serial data stream that is called a ____________.
The ________________ is the path from your facility to and from the outside world.
What are the three types of Command Communications Service Designators (CCSD)?
Permanent, spare and temporary
Which type of circuit retains its CCSD until deactivated and is assigned by DISA?
A _____________ CCSD is assigned to a channel that does not carry an active circuit.
____________ CCSDs are generated when a user requests a service that does not warrant a permanent CCSD and needs the circuit for 7 days or less.
An ______________ report is submitted when the service meets all details of the TSO and is fully operational.
A ____________ report is submitted when the customer cannot use the circuit.
One of the oldest and commonly used standards for DTE to DCE interfacing, which supports up to 20,000 bits per second in full or half-duplex mode and asynchronous data flow and uses a 25-pin connector and negative logic.
What kind of interface is RS232C/EIA-232D?
Standard that allows for use of a db-25 connector, offers rates of 20 Kbps at 4000 feet to 2 Mbps at 200 feet and is used for both asynchronous and synchronous interfaces.
What kind of interface is RS-530?
Standard that is a high-speed interface for data transmission of 1.2 Kbps at 3000 feet to 2Mbps at 50 feet and sends balanced data signals and unbalanced control signals.
A type of bipolar signal that sends all digital 0s at 0V and alternates the digital 1s from positive to negative polarity.
Alternate Mark Inversion (AMI) Format
Digital signal format in which each bit (regardless of polarity) returns to 0V condition at half the duty cycle or bit time.
Digital signal format which does not allow the signal level to return to 0V between successive bits or during the bits duty cycle or bit time.
Non-Return-To-Zero Format (NRZ)
An analog signal that has digital information coded on to it to allow digital signals to travel longer distances on an analog path.
Flow control that is sometimes referred to as RTS (Request-to-send)/CTS (Clear-to-Send) flow control and requires that extra input and output lines are used on the serial device to perform handshaking.
Hardware Flow control
Flow control also known as XON-XOFF ("transmit on" and "transmit off") flow control, in which bytes are sent to the sender using the standard communication lines.
Software Flow control
What are the primary protocols in synchronous communication?
What are the primary jobs that synchronous protocols perform?
Format data into blocks known as "frames"
Add control information
Check the information to provide error control
Digital timing method in which data is transmitted in continuous streams, but without an external clock signal.
_______ refers to the speed at which information moves across the media.
A _________ is the time it takes to send a character, including any start and stop bits.
A measurement of the signaling speed of a data transmission device.
________ is a measure of throughput or rate of data transfer and represents the number of bits that are transmitted within a second and it is measured in bits per second.
_________ is nothing more than counting the number of bits received in a specific time interval (usually one second).
Bit Count Integrity
Who uses the AF Form 3215 to prepare a Telecommunications Request and where do they send it?
The local System Control Facility (SCF) and they enter it into DISA Direct which is then routed to MAJCOM Telecommunication Certifications Office (TCO) who will certify and validate the TR.
A request for service that details the type of services, service locations, and other pertinent information required to specify parameters to the agency or commercial carrier providing the service.
Telecommunications Service Request (TSR)
Who prepares a Telecommunications Service Request (TSR) and what happens to it?
MAJCOM Telecommunication Certifications Office (TCO) prepares it and updates it to DISA direct, which routes it to the DISA action activity/agency responsible for providing the required service and to other agencies/units as necessary.
The process of providing telecommunications service to a user.
The process of returning a defective circuit back to operation through either repair or alternate routing.
Process that involves "appropriating" a circuit of lesser importance (lower priority) to allow a higher priority user to communicate when ther are no spare channels or equipment available.
The part of the TSP Authorization code that is a computer-generated ID for tracking purposes which occupies the first through ninth positions.
TSP Control Identifier
The part of the TSP Authorization code which occupies the eleventh and twelfth positions and is used to assign the priority for provisioning and restoration purposes.
A complete path between two end terminals over which one-way or two-way communications may be provided.
For multiple users, it is where the local user's information accesses a multiplexer. For single users, it is the physical or logical path allowing the transmission of information: the path connecting the sender to the receiver.
The entire path the signal has to travel through, including all equipment in order to get from the sender at one station to the receiver at the distant end.
A _______ differentiates one particular circuit from another to eliminate guesswork and confusion.
CCSD (Command Communications Service Designator)
Spare channels that spare CCSDs are assigned to are subdivided into what two categories?
digital (DC) and audio (VF)
The one organization authorized to negotiate and write contracts for commercial telecommunication services and the government liason for communication contractors and the DoD.
What is sent from DITCO to let the SCF know about an order status if a required service uses commercial services or equipment?
Status Acquisition Message (SAM)
A Status Acquisition Message (SAM) is received for what reasons?
1. Time for installation of the leased service at your facility
2. Contract service has been completed
3. Delay in service
4. Any additional information that is required
5. Contractor supplies information (i.e. reference number, cost, service date).
An ____________ is submitted when a service has not yet met the technical parameters required, but its close enough for the customer can use it to pass their information on it.
What is a link defined as?
A link is the path that your facility connects to and from the outside world; it is the composite (logical) communication line between two locations.
What are the three reasons for installing a mux?
It saves on communication costs, it has inherent error correction and inherent data security.
What must someone wishing to “tap” into a muxed signal know in order for the data to have any value?
They must have the link protocol and know the individual channel assignment schemes and data formats.
What is an example of FDM?
a series of different radio or TV stations
In TDM, data streams are assigned what?
a different time slot in a set
Explain the differences between synchronous and asynchronous in reference to TDM.
In synchronous TDM, each signal is given a unique, but equal timeslot for its information.
Asynchronous TDM is the same as synchronous except that the amount of time per slot is variable.
List and describe the advantages and disadvantages to Time Division Multiplexing (TDM).
Advantages of TDM:
· No band pass filters per channel eliminates group delay.
· No guard bands make it more bandwidth efficient.
· Asynchronous TDM has improved efficiency as time slots can adjust width, within limits, to accommodate traffic.
Disadvantages of TDM:
· Expensive terminal devices (digital converters) when compared to FDM (analog converters) units. For example, digital TV.
· Requires precise timing.
What is the communications discipline used between two multiplexers?
Explain why Asynchronous Time Division Multiplexing has improved efficiency.
Asynchronous TDM has improved efficiency as time slots can adjust width, within limits, to accommodate traffic.
A T-1 line has how many DS0's?
A T-1 signal operates at what speed?
What are the two predominant types of T-1 framing?
What are the two predominant types of T-1 coding schemes?
Alternate Mark Inversion (AMI) and Bipolar 8 Zero Substitution (B8ZS)
A ___________ performs the function of combining several data or voice communication channels into one composite signal, which can be transmitted between two locations cheaper than the cost of individual lines.
___________ multiplexing can be described as dividing the circuit “horizontally” so that many signals can travel a single communication circuit simultaneously.
The unused portions of the circuit that separate frequencies from each other to prevent cross-talk.
________ involves the distribution of multiple signals in the time domain, a digital process.
TDM (Time Division Multiplexing)
What are the two major types of Time Division Multiplexing (TDM)
1. Synchronous TDM
2. Asynchronous TDM
What is the standard speed of an individual digital circuit and what is it called?
64 Kbps and it is called DS0
What system is the most widely used system for the transmission of time division multiplexed digital signals.
What is the building block for all multiplexed digital data networks?
T-1 or Trunk Level 1
How many multiplexed DS0s equal a DS1?
T-1 Framing format that consists of 12 individual and consecutive DS1 frames.
D4 Superframe (SF)
T-1 Framing format that is 24 frames and provides enhanced signaling and error testing capabilities over D4 framing.
Extended Superframe (ESF)
T-1 Coding scheme that causes the line to alternate between positive and negative pulses for successive 1's (marks).
Alternate Mark Inversion (AMI)
T-1 Coding scheme takes advantage of Bipolar Violations (BPVs) and utilizes them to indicate that the user's data contains a long string of zeros.
Bipolar 8 Zero Substitution
Method of serial data transmission in which a clock signal is required to send data and maintain synchronization.
Method of serial data transmission in which data is transmitted in between a start and a stop bit in order to maintain synchronization.
A version of FDM (Frequency Division Multiplexing) used in fiber-optic cables.
Wave Division Multiplexing
What does the WDM (Wave Division Multiplexing) unit consist of?
A Signal Processing Facility (SPF), a Multiplexor (Mux) which is responsible for joining the signals at the transmitting end, and a DeMultiplexer (DeMux) which is responsible for splitting the signals at the receiving end.
Generally speaking, what are the sources from which timing can be derived?
Internal and external sources
A crystal oscillator is an example of which type of clock?
What are three types of external timing?
Atomic clocks, gps and recovered timing
What are the two most widely used types of atomic clocks?
Cesium beam and rubidium atomic clocks
How many satellites comprise the GPS?
Which Air Force Base has the responsibility of updating the GPS satellite atomic clocks?
Schriever AFB, Colorado
What does a recovered clock use to develop timing?
Recovered timing develops its timing signal from the transitions in a receive data stream.
The most precise atomic clock, which operates best in a stable environment.
cesium beam atomic clock
Commonly used atomic clock that is used more in tactical environments.
rubidium atomic clock
What is the maximum number of local users the FCC-100 can multiplex?
List the five common modules in the FCC-100.
Front Panel Interface Module
Port Carrier Module
What does the processor module do?
The processor module supervises FCC-100 operation and communicates with all the other FCC-110 modules and subassemblies.
What does the MUX/DEMUX module do?
The mux/demux module does the multiplexing and demultiplexing of data between the aggregate and ports.
What is the function of the aggregate module?
The aggregate module provides the interface between the multiplexer and the transmission media going towards the distant end.
What is the maximum number of local users a port carrier card can interface?
A port carrier card can interface up to two local users.
What is the function of the port carrier module?
The port carrier module provides the user transmission media interface and cable termination for two local user channels.
What is the function of the front panel interface module?
The front panel interface module is the communication link between the processor module and either the operator's panel or an external control terminal.
What is the function of the Operator's Panel?
The operator's panel contains all the necessary functions to allow you to interface with the processor module.
Which connections on the FCC-100 backplane are designated for local users?
J1 through J16
What is the function of jack 18 of the Backplane?
J18 provides the capability for remote alarm monitoring.
What is the function of jack 19 of the Backplane?
J19 accommodates a control terminal which allows a technician to "console" into and configure the FCC-100 remotely
What is one tool to help you diagnose FCC-100 problems?
What is the difference between a local and remote loopback?
Local loopback is when the loop is occurring on the local FCC-100.
Remote loopback is when the loop is occurring on the distant-end FCC-100.
The ______ of the FCC-100 is where you connect the user's cable and power to the device.
Type of loopback in which the multiplexer loops back its own transmit data to itself and sends a constant mark to the distant end multiplexer.
Type of loopback in which the multiplexers transmit data is looped back from the distant end multiplexer.
ATM is a method of communication that is used for WAN‟s only. True or False?
Describe and explain the parts of the ATM cell.
header: (5 bytes) addressing mechanism
payload: (48 bytes) portion that carries the actual information - voice, data, or video
Explain what the ATM layer of the ATM architecture does.
The ATM layer takes the data to be sent and attaches the 5-byte header information to the payload, thus assuring the cell is sent on the right connection.
Explain the purpose of the Adaptation layer of the ATM architecture.
The Adaptation layer assures the appropriate service characteristics and divides all types of data to be inserted into (or extracted out of) the 48-byte payload that will make up the ATM cell.
Explain what the Physical layer of the ATM architecture does.
The ATM physical layer manages the medium-dependent transmission converting to appropriate electrical or optical format.
List 6 key benefits that ATM offers.
-One network for all traffic
-Enables new applications
-Simplified network management
-Long architectural lifetime
Explain the difference between the NNI and UNI headers on ATM cells.
The UNI header is used for communication between ATM endpoints (users) and ATM switches in private ATM networks.
The NNI header is used for communication between ATM switches.
ATM is a method of communication that can be used for both ______________ and __________________ technologies.
What is the job of an ATM switch?
The job of an ATM switch is to accept the incoming cell from an ATM endpoint or another ATM switch.
How many bytes long is the ATM cell?
What are some examples of ATM endpoints?
Users or workgroups
Which layer is responsible for cell transit through an ATM network?
Which layer, or layers, of the ATM model reference the Data Link layer of the OSI reference model?
ATM adaptation layer
List and explain the two types of physical connections that ATM supports.
point-to-point and point-to-multipoint
What is the basic function of the LANE protocol?
The function of the LANE protocol is to emulate a LAN on top of an ATM network and to resolve MAC addresses to ATM addresses.
The only standards based technology that has been designed from the beginning to accommodate the simultaneous transmission of data, voice and video ranging in speeds from Megabits to Gigabits.
ATM (Asychronous Transfer Mode)
What are the three layers of the ATM reference model?
ATM Adaptation Layer
Which layer of the ATM reference model defines the electrical characteristics and network interfaces?
An ATM network is made up of what?
ATM switches and ATM edge devices
What are examples of ATM edge devices?
workstations, routers, digital service units (DSUs), LAN switches, and video coder-decoders (CODECs)
ATM physical connection in which two ATM end systems are connected and can be unidirectional (one-way communication) or bi-directional (two-way communication).
ATM physical connection in which a single-source end system (root node) is connected to multiple destination end systems (leaves).
What are the two types of ATM connections that exist?
Virtual channels (end-to-end connection between terminal devices), which are identified by a virtual channel identifier (VCI)
Virtual paths, which are identified by virtual path identifiers (VPI)
What are the two types of ATM services that exist?
Permanent Virtual Circuits (PVC)
Switched Virtual Circuits (SVC)
ATM service that allows direct connectivity between sites.
Permanent Virtual Circuit (PVC)
What are the advantages and disadvantages of Permanent Virtual Circuits (PVC)?
Advantages are that a PVC guarantees availability of a connection and does not require call setup procedures between switches and it is most effective for connections between hosts that communicate frequently.
Disadvantages include static connectivity and manual setup.
ATM service that is created and released dynamically and remains in use only as long as data is being transferred.
Switched Virtual Circuits (SVC)
What are the advantages and disadvantages of Switched Virtual Circuits (SVC)?
Advantages include connection flexibility and call setup that can be handled automatically by a networking device.
Disadvantages include the extra time and overhead required to setup the connection.
What are disadvantages of ATM?
Overhead of cell header
Complex mechanism for achieving Quality of Service
ATM equipment is very expensive and requires extensive training in order to maintain properly.
Congestion may cause cell loss.
A Promina module consists of how many cards?
The Promina 200 contains how many physical slots?
Slot 0 on the Promina 200 is reserved for which card(s)?
Promina Logic Module (PLM).
Which module has the capability to accept an external clock for network synchronization?
Universal Synchronous Data (USD) Module
How many ports can be configured on the PVA card?
List and describe the contents of flash memory.
Flash memory stores boot code,system software and configuration database.
Explain the functions of both the front and rear cards of a module.
The front cards contain the logic circuitry for their specific function.
The rear cards provide physical interfaces to devices external to the multiplexer.
How many Load Units does the Promina Logic Module have? How many Load Units does it use for its own functions?
32 load units, 4 used for its own function
What does the Promina Logic Module (PLM) provide to the Promina 200?
The PLM provides the processor platform (25 MHz), clock, and switching matrix for the Promina 200.
What card does the Promina 200 use for internal timing?
High Speed Synchronous Data (HSD-2) Module.
Define Logical Slot.
The unit of measurement we use for available bandwidth is the logical slot. A logical slot = 2.048 Mb/s.
Define Load Unit.
Load units are used to measure a module's processing power consumption.
Each shelf of the Promina 200 contains how much bandwidth?
Each shelf contains 32.768 Mb/s of bandwidth.
What is the speed of the processor on the Promina 200?
The PLM contains how much flash memory?
16 MB (expandable to 32 MB)
What do the front and rear cards plug into?
A front and rear card together are called a ______.
Which card is the processor module for the Promina 200?
What two categories do all modules of the Promina 200 other than the PLM fall into?
Port Side or Trunk Side modules
Category of modules on the Promina 200 that allows users to access the Promina Network.
Port Side modules
Category of modules on the Promina 200 that provides connectivity to other Promina Nodes.
Trunk Side modules
The rear interface card for the PLM, which provides the operator access to configure, monitor and diagnose the Promina network is known as what?
The module that is a two-di-group, clear channel interface that supports the T1 digital voice interface.
Primary Rate Card (PRC)
Module that provides the user with analog voice services and is responsible for converting voice signals from analog to digital and from digital to analog.
Prime Voice Analog (PVA) Module
Module on Promina 200 that multiplexes data from Port side modules into a proprietary bundle of DS0s and has an STI rear card programmed to interface with RS-530 equipment.
Trunk 3 (TRK-3) Module
Module on Promina 200 that supports symmetric full-duplex (two-way) and simplex (one-way) calls in asymmetric trunk mode.
Symmetric Asymmetric (SA-TRK) Module
Module on Promina 200 that provides transmit and receive timing, non-transparent signaling, CTS signal following RTS with zero delay, remote and local loop through the switch signal or the O/I, additional port speeds, and channelized data in the Nx56/64 kbps PRC format.
High Speed Synchronous Data (HSD-2) Module
Module on Promina 200 that provides the user with the capability to connect DTE or DCE devices into the Promina network.
Universal Synchronous Data (USD) Module
Device not physically part of the Promina multiplexer, but needed to convert the RS530 output of the TRK-3 module to a T1 format, as well as being able to do several types of loop-back tests and bit error rate tests.