Telephone networks and systems

1) if there are 2800 maximum cell arriving per hour to a trunk circuit without blocking, calculate the offered traffic for an average calling time of 1.76 minutes and compute the GoS for 2812 simultaneous calls.a)82.13 Erlangs, 0.43% b)74.18 Erlangs, 0.22%c)143.66 Erlangs, 0.22% d)88.88 Erlangs, 0.34%

2) if a groups of user made 32 calls in one hour, and each call had an average call duration of 5 minutes, this is equivalent to how many Erlangs of traffic .a)1.5 Erlang b)8.5 Erlangc)12.4 Erlang d)2.5 Erlang

3) the range of Dc current that flows through a telephone is?a)20μA to 80μA b)200μA to 800μAc)2mA to 8mA c)20mA to 80mA4) calculate the blocking probability for a group of 6 trunks that is designed to carry 3 Erlangs of traffic intensity using the Erlang B formula.a)3.33% b)2.22%c)6.33% d)5.22%5) what frequencies are used in pressing 5?a)770 Hz, 1336 Hz b)852 Hz, 1336 Hzc)770 Hz, 1209 Hz d)852 Hz, 1633 Hz6) the separation of control functions from signal switching is known as:a) step-by-step switching control b)crossbar controlc)common control d)ESS7) find the holding time if 300 calls registered 13.5 Erlang traffica)27 s b)261 sc)162 s c)22.23 s8)”bit-stuffing” is more formally called:a)compensation b)rectificationc)justification d)frame alignment9) if we wish to have 10 mile long subscriber loop with a total resistance of 1300 ohms, find the diameter of the copper conductor to be used.a)0.0812 in b)0.029 inc)0.0632 in d)0.03256 in10) for a certain telephone, the DC loop voltage is 48V on hook and 8V on off hook. If the lopp current is 40mA, what is the DC resistance of the local loop?a)1300 ohms b)1500 ohmsc)1000 ohms d)2300 ohms

11)for a certain telephone the DC loop voltage is 48V on hook and 8V off hook.If the loop current is 40mA, what is the DC resistance of the telephone?a)48 ohms b)200 ohmsc)40 ohms d)1300 ohms12) the typical voltage across the telephone when on hook is:a)48 volts DC b)48 volts, 20 hertz ACc)90 volts DC d)90 volts, 20 hertz AC13)if a telephone voice signal has a level of 0 dBm, what is its level in dBrn?a)-90 dBrn b)-85 dBrnc)90 dBrn d) 85 dBrn14)in DS-1, bits are”robbed” in order to:a)provide synchronization b)carry signalingc)cancel echoes d)check for errors15)a telephone test-tone has a level of 80dBrn at a point where the level is +5dB TLP. If C-weighting produces a 10-dB loss, what would the signal level bein dBrnc0?a)80 dBrncO TLP b)65 dBrncO TLPc)60 dBrncO TLP c)75 dBrncO TLP16) what is the approximate data rate for a system using 8 bits per sample and running at 8000 samples per second?a)56 kbps b)128kbpsc)64 kbps d)384 kbps17)if bits were “stolen” from every DS-1 frame, what would the usable data-rate be for each cahnnel frame?a)64 kbps b)8 kbpsc)128 kbps d)56 kbps18)POTS stands for:a)private office telephone system b)primary office telephone systemc)primary operational test system d)plain old telephone system19)calculate the traffic flow in call-minute and call-hour if 100 calls are generated in 1 hour of 3 minutes average duration.a)260 call-minute, 4 call-hour b)600 call-minute, 10 call-hourc)300 call-minute, 5 call-hour d)480 call-minute, 8 call-hour20)Dc current flow through a telephone:a)when it is on hook b)when it is off hookc)as long as it is attached to a local loop d)only when its ringing21)calculate the dB of VNL for a channel with 3 ms delay.a) 1 db b)1.4 dB

c)0.4 dB d)0.8 dB22) determine the actual traffic carried by a group of trunks with an offered traffic of 20 Erlangs and 0.98785 blocking probability.a)1.113 Erlang b)0.243 Erlangc)6.743 Erlang d)13.756 Erlang23)signal loss is designed into a telephone system to:a)eliminate reflections b)prevent oscillationc)improve signal to noise ratio d)reduce power comsumption24)calculate the blocking probability for a group of 4 trunks that offers 10 Erlangs of traffic and a trunk efficiency of 88%a)0.8666 b)0.64666c)0.9666 d)0.46625)call blocking:a)cannot occur in public telephone networkb)occurs on the local loop when there is an electrical power failurec)occurs only on long distance cablesd)occurs when the central office capacity is exceeded26)a single GSM carrier supports 8(TDM) speech channels. If the traffic volume is 129.6 ccs. How many 3 minute calls does this represent?a)172 calls b)7.2 callsc)72 calls d)720 calls27)the typical voltage needed to “ring” a telephone is:a)48 volts DC b)48 volts, 20 Hz ACc)90 volts DC d)90 volts, 20 Hz AC28)VNL stands for:a) voltage net loss b)volume net lossc)via net loss d)voice noise loss29)if we know that there are 512 siezures(lines connected for service) and 24 blocked calls(lost calls) during the BH, what is the grade of service?a)0.017 b)0.032c)0.045 d)0.06730) SLIC stands for:a)single line interface circuit b)standard line interface cardc)sunscriber line interface card d)standard local interface card31) on a particular traffic relation the calling rate is 461 and the average call duration is 1.5 min during the BH. What is the traffic intensity in CCS?a)345.75 CCS b)414.9 CCSc)1152.5 CCS d)691.5 CCS

32)the reference noise level for telephony is:a)1 mW b)0 dBmc)1 pW d)0 dBr33)in loading cable 26B66 means_______.a)26 gauge every 2000 ft with 66 pH conduntorsb)26 gauge every 4000 ft with 66 pH conduntorsc)26 gauge every 3000 ft with 66 pH conduntorsd)26 gauge every 6000 ft with 66 pH conduntors34) the BRI requires _______ kbps of digital transmission capacity without overhead.a)64 b)144c)128 d)192

35)PSTN stands for:a)public switched telephone networkb)private switched telephone networkc)primary service telephone networkd)primary service telephone numbers

36)0.005 GoS means_____.a) 1 call in 20 would be lost because of insufficient equipment.b) 2 call in 400 would be lost because of insufficient equipment.c) 5 call in 100 would be lost because of insufficient equipment.d) 10 call in 20000 would be lost because of insufficient equipment.

37) how many connection are needed to connect 50 subscribers directly?a)2125 b)2450c)1225 d)2521

38)a T-1 multiplexer has____ channels.a)12 b)24c)96 d)32

39)in ISDN, the _____ is a 16 kbps or 64 kbps digital channel used to carry signaling information.a)D-channel b)A-channelc)B-channel d)C-channel

40)the number of voice channels in a basic FDM group is:a)6 b)12c)24 d)60

41)calculate the blocking probability for a group of 4 trunks that offers 10 Erlangs of traffic and a trunk efficiency of 2.6%

a)0.8966 b)0.966c)0.98966 d)0.86642)local loops terminate at:a) a tandem office b)a toll stationc)a central office d)a interexchange office

43)determine the actual traffic carried by a group of trunks with an offered traffic of 10 Erlangs and 0.64666 blocking probability.a)3.533 Erlang b)0.7193 Erlangb)8.134 Erlang d)12.444 Erlang

44)a particular exchange has been dimensioned to handle 1000 calls during the busy hour. On a certain day during BH 1100 calls are offered. What is he resulting grade of service?a)1 b)10c)0.01 c)0.1

45)loading coils were used to :a)increase the speed of the local loop for digital datab)reduce the attenuation of voice signalsc)reduce crosstalkd)provide C-type conditioning to a local loop

46)PRI in ISDN consist of 23 or 30B-for user data and a single _____ kbps D-channel for signalinga)16 b)32c)64 d)48

47)how long does it take to dial 1234560 in sec using pulse dialinga)1.5 sec b)3.4 secc)4.8 sec d)6.1 sec

48)ADSL stands for:a)all-digital subscriber line b)asymmetrical digital subscriber linec)allocated digital service line d)access to data service line

49)_____ refers to the percentage of time a circuit or faculty in usea)reliability b)trafficc)occupancy d)availability

50)wht is the mean holding time if the traffic carries is 4.56 Erlang. The number of calls received is 200 in given EBHC?a)273.6 sec b)41.04 secc)14.08 sec d)82.08 sec

51)the 23 B+D channel used in North American and Japan uses total transmission capacity of ___Mbps with overhead.a)2.048 b)1.920c)1.536 d)1.544

52)a group of trunks offered 10 Erlangs of traffic, 0.002 GoS. Calculate the trunk efficiency assuming 20 trunks.a)49.9% b)89.9%c)29.9% d)69.9%

53)in loading cable 19H88 means ______.a)19 gauge every 3000 ft with 88 μH inductorsb)19 gauge every 6000 ft with 88 μH inductorsc)19 gauge every 2000 ft with 88 μH inductorsd)19 gauge every 4000 ft with 88 μH inductors54)a group of 20 subscribers generate 50 calls with an average holding time of 3 minutes, what is the average traffic per subscriber?a)0.125 Erlang/subscriber b)12.5 Erlang/subscriberc)0.0125 Erlang/subscriber d)1.25 Erlang/subscriber55) if there are 3000 calls arriving per hour to a trunk circuit with an average calling time of 1.76 minutes, calculate traffic intensity.a)48 Erlangs b)88 Erlangsc)68 Erlangs d)78 Erlangs56)traffic _______ is the sum of the holding times of the traffic carried by a pool of resources over a given period of time.a)capacity b)volumec)transit d)intensity57)calculate actual data rate of T3 facilities.a)45.078 Mbps b)44.736 Mbpscc)1.728 Mbps d)44.008 Mbps58)a switching machine is set to accept pulsed at a rate of 10 pulses/sec with 60% break, find the make interval of the switch.a)0.4 s b)0.6 sc)40 ms d)60 ms59)the BRI in ISDN consist of ________ B-channel (S) and D-channel.

a)1 b)23c)2 d)3060)a data transmission facility is encapsulating 4096 bytes of data to form a single packet. Assuming the system is using T1 line, hoe may packets are transmitted per second ingnoring overhead.a)57.12 packets b)47.12 packetsc)67.12 packets d)77.12 packets61)a switch could support a maximum of 9800 siezures during the busy hour. Calculate the number of block calls during the BH if the GoS is 0.245%a)49 calls will be block b)12 calls will be blockc)24 calls will be block d)96 calls will be block62)on particular traffic relation, the calling rate is 825. If the traffic intensity is 990 CCS during the BH, what is the average call duration?a)2 minutes b) 12 minutesc)6 minutes d)8 minutes63)A telephone signal takes 2 ms to reach its destination. Calculate the VNL required for an acceptable amount of echo.a)0.2 dB b)0.8 dBc)06 dB d)0.4 dB64)the ff. information was recorded in a 5 trunk network from 9:00-10:00 amTrunk 1 48 minutes2 56min and 28sec3 18 minutes4 25min and 24sec5 42minutesFind the traffic carried by the network in Erlanga)18.20 Erlang b)3.16 Erlangc)0.781 Erlang d)5.82 Erlang65)in ISDN, the _______ is a 64 kbps digital channel that can carry a user data or digitized voice.a)A-channel b)C-channelc)B-channel d)D-channel66)a duration of traffic occupancy from a call, sometimes referred to as an average duration of occupancy of one or more path from calls.a)traffic b)average callc)busy hour d)holding time

67)out of the total capacity required by the BRI ______ kbps is used overhead.a)48 b)144c)64 d)1668)find the maximum length of the subscriber loop with the ff. specs. Allowable loss of 6dB using a #24 cable and resistance limit of 1200 ohms.a)7.19 kft b)13.73 kftc)14.63 kft c)11.76 kft69)one Erlang is equal to _____?a)360 CCS b)3.6 CCSc)100 CCS d)36 CCS70)what is the line rate of T1 and E1 respectively?a)2.048 Mbps and 1.544 Mbps b)384 Mbps and 2.048 Mbpsc)1.544 Mbps and 2.048 Mbps d)1.455 Mbps and 2.408 Mbps71)______ is the type of telephone switch having vertical and horizontal paths, and electromagnetically operated means for interconnecting any one of the vertical paths with any of the horizontal paths.a)cross bar b)step by stepc)strowger d)hybrid72)what is a leased line?a)a piece of wire used in local area network in one buildingb)a piece f wire connecting a telephone set to a PABXc)a temporary connection of one computer to a mainframe via a modern and a telephone lined)a permanent circuit for a private use within a communication network73which of the following device increases the battery voltage on a loop and extends its signaling range?a)VF repeater b)VF amplifierc)loop extender d)BORSCHT74)one Erlang of traffic is equal to ______ call seconds.a)60 b)1800c)360 d)360075)the 23 B+D channel used in north America and japan uses total transmission capacity of _____ Mbps with overhead.a)1.536 b)1.544

c)2.048 d)1.92076)blocked calls delayed condition specified delay probability.a)Erlang B b)Erlang Cc)Erlang D d)poisson77)a (an) _____ call attempt is one that cannot be further advanced towards its destination due to an equipment shortage or failure in network.a)lost b)abandonedc)barred d)terminated78)in TDM, multiple signal share a channel by transmitting in different a) intervals b)frequency bandsc)sampling rates d)amplitudes79)____ is a telephone service which enable to user to dial directly telephones outside the user’s local area without the aid of the operator.a)ISDN b)DDDc)DID d)bypass80)the point between the network termination equipment and the terminal equipment is known as the _____ reference point.a)R b)Uc)L d)S81)terminal equipment which are non-ISDN compatible can be attached to an ISDN network by using a speciala)modem b)front end processorc)terminal adapter d)bridge82) terminal equipment which are ISDN compatible are generally referred to as a)TE1 b)IBPc)smart terminals d)dumb terminals83)the basic switching element in a PAM multiplexer is a (an)a)ADC b)MOSFETc)DAC d)bandpass filter84)in PCM, analog signals are transmitted asa)supergroups b)pulsesc)binary codes d)packets

85)the time period which all channels are sampled once is calleda)slot b)domainc)cycle d)frame

86)______ is a voice operated device that inserts a high loss in the opposite direction of transmission of the talking party.a)hybrid b)2 wire circuitc)VNL d)Echo suppressor87)______ is a signal returned to the talker after making one or more round trips between the talker and the listenera)singing b)jitterc)echo d)crosstalk88)the BRI in ISDN consists of _______ B-channel (S) and D-channel.a)1 b)2c)3 d)489)an even faster class of ISDN interface standards presently being developed is calleda)narrowband ISDN b)broadband ISDNc)ATM d)frame relay90)current ISDN standards requires twisted pairs for the PRI transmission a) 3 b)6c)1 d)291)Traffic ______ is the sum of the holding times of the traffic carried by a pool of resources over a given period of timea)volume b)transitc)intensity d)capacity92)________ is a service in which a telephone or PBX location is directly connected to a central office in a distant city via a private line , instead of being connected directly to the central office in that location.a)bypass service b)remote switching unitc)foreign exchange d)diversion

93)a signaling method with set combinations of two specific voice band frequencies, one of which is selected from a group of 4 lower frequencies and the other from a group of 3 or 4 relatively high frequencies .a)out of band b)channel associatedc)in band d)DTMF

94)PABX meansa)private all purpose broadcasting exchangeb)public access bi-directional exchangec)private automatic branch exchanged)public automatic branch exchange95)in ISDN, the ______ is a 64Kbps digital channel that can carry a user data or digitized voicea)A-channel b)C-channelc)B-channel d)D-channel96)ISDN is defined as the network that provides an end to end ______ to support a wide range of services including non-voice services.a)transparency b)switchingc)connectivity d)interfacing97)the international body which issues recommendations for standards relating to telecommunications is thea)IEEE b)ETSIc)CCIR d)CCITT98)the multiplexer and de-multiplexer are kept in a step with one another by a (an)a)clock b)headerc)sync pulse d)sequencer99)a _______ is a local automatic telephone office serving extensions is a business complex and providing access to the public network.a)concentrator b)FEXb)PAX d)PABX100)a T-1 multiplexer has ______ channels.a)24 b)32

c)64 d)1024101)the standard word size in PCM audio system is ____ bitsa)16 b)8c)32 d)64102)the primary benefit of multiplexing isa)redundancy b)economyc)speed d)error detection

a)a signal of the same amplitude but 180 degrees out of phase from the original signal and mixed with the original signal at the transmitter toproduce more negligible output signal.b)a wave which has been reflected or otherwise returned with sufficient magnitude and delay for it to perceptible in some manner as a wave distinct from that directly transmitted.c)the signal having a higher frequency than the original and transmitted backto earth by a passive satellite.d)reflected signal.104)what is a communication link ?a)it is a channel or circuit intended to connect other channels or circuits.b)it is a piece of wire that is connect to the ground terminals of all communication sequipments in one establishment.c)it is a cable connecting a transmitter to the antenna.d)it refers to a radio link.105)the ISDN network equipment which are installed in the customer premises is Called the ___ equipment?a)terminals b)DTEc)adapter d)sever106)A voice grade channel is suitable for transmission of?a)signals with a frequency from 3400 hzb)VHF signalsc)UHF signalsd)VHF and UHF signals

107)what is trunk?a)the base of the communications towerb)a line connecting the telephone set to a PABXc)a telephone line connecting two central officesd)refers to the body of the tree108)what is a four-wire circuit?a)is a circuit with three output terminals and one input terminalb)is used between serving central offices for long distance connction with one being pair being used for each drction of transmissionc)is an oscillator that produces stimultaneously for different frequencies d)a circuit consisting of four transmission lines109)for every button pressed on the touch tone telephone ,how many signals are Transmitted to the CO?b)two audio frequency tonesc)one VHF signal and one audio frequency tone d)three audible tones 110)the physical connection between the telephone set at the switching equipmentIs called the a)trunk line b)linkc)subscriber loop d)leased line 111)the transmission of information from multiple sources occuroring in the same a)FDM b)TDMc)WDM d)CDM112) the BRI requires _______ kbps of digital transmission capacity without overheada)64 b)144c)128 d)192113)what is an Erlang?a)it is equal to the number of simultaneous calls originated during a specific hourly periodb)it is a unit of magnetic field intensity measured around a conductor c)it is the number of erroneous bit receive per unit of timed)it is unit of electrical energy radiated in space

114)the PRI in ISDN consist of 23 or 30B-for user data and a single _____Kbps D-channel for signalinga)16 b)23c)32 d)64115)what is the traffic model about blocked calls cleared condition specified blocking probabilitya)Erlang B b)Erlang Cc)Erlang D d)poisson116)a touch tone telephone generates how many different tones?a)10 audio frequency tones b)8 audible tone frequenciesc)4 VHF signals d)16 audio frequency tones117)________ is the operation of the switch selector in searching terminals until an idle one is founda)hunting b)insulation effectivec)elective d)loop118)what is a concentration?a)a system that improve the signal to noise ratio by compressing the volume range of a signalb)a switching system that lets a large number of transmission lines or a narrower bandwidthc)a device that varies the characteristics of a carrier signal in the accordance with the waveform of the modulating signal which contains a useful informationd)an equipment in the central office119)which of the ff. wire is used to transmit the signal?a)black b)greenc)yellow d)red120)a device converts a 2 wire circuit into a 4 wire circuita)RS 232 interference b)hybrid circuitc)balun d)stub121)a passive _____ is an electronic device which reduce the signal strength by a specified amount in dBa)splitter b)filterc)himmer d)attenuator

122)what is a multi drop line?a)a line or circuit interconnecting in several stationsb)a piece of wire with a thick insulating that serves to protect the conductive material form damage in the event the wire is droppedc)a line designed to withstand a high pressured)a bus line123)____________ is a trunk between two central offices in the same switching center complexa)intraoffice b)foreign exchangec)intertoll d)ileline124)AWG #26 has a typical loss ofa)0.21dB/1000ft b)0.32dB/1000ftc)0.51 dB/1000ft d)0.41 dB/1000ft125)which of the ff. is commonly used in wire for subscriber loop design?a)AWG #18 b) AWG #30c) AWG #33 d) AWG #19

126)what is singing?a)an undesired self sustained oscillation in a system, generally caused by excessive positive feedbackb)the result of the intermodulating two or more signals of different frequencies to produce a tone having a frequency higher than that of the highest frequencyc) the result of the intermodulating two or more signals of different frequencies to produce a tonehaving a frequency equal to the sum of the frequencies of te signals intermodulatedd)the art of entertainment that can make one rich127)_________ is the uninterrupted of 60 minutes for which the average intensity of traffic is at the maximuma)maximum access time b)busy hourc)maximum occupancy d)peak traffic128)_________ is the probability of the call being blocked during the busy hour because of insufficient equipment or trunks

a)contention b)grade of servicec)poisson distribution d)lockout129)presently this the standard frequency bandwidth for voice transmissiona)300 to 3400 Hz b)0 to 4000 Hzc)100 to 3400 Hz d)300 to 3000 Hz130) the resistance limit for no. 2 crossbar exchange (US) isa)2000 ohms b)1250 ohmsc)1300 ohms d)1200 ohms131)what is the standard voice channel spacing?a)44 MHz b)4 KHzc)40 KHz d)40 MHz132)which of the ff. responds to the request of the subscriber by sending a dial tone?a)line finder b)connectorc)first selector d)line equipment133)combination of modulator channel and detectora)transceiver b)transponderc)discrete channel d)T/R channel

134)it is a advantage of a side tonea)transmission efficiency is increasedb)assures the customer that the telephone is workingc)speaker increases his voice resulting in strengthen signald)no dissipation of energy in the balance of network135)what is a two wire circuit?a)a circuit usually on the subscribers loop, between the telephone set and the local control officeb)a circuit having two terminals, both terminals having the same instantaneous voltagec)a circuit with the input terminal, one output terminal and a common groundd)a circuit consisting of two transmission lines

136)what is the local loop of the telephone system?a)it is a group of wires connecting a telephone set to a modemb)it is a four wire circuit connecting a facsimile machine into a computerc)it is a two wire or four wire communication circuit between the customers premise and the central officed)it is a single piece of wire connecting the subscriber telephone set into another set in an adjacent room137)the corresponding frequency for the digit 7 in the touch tone telephone isa)770 and 1477 Hz b)852 and 1209 Hzc)852 and 1336 Hz d)770 and 1336 Hz138)the D-channel messages in an ISDN network are ______ switcheda)circuit b)timec)packet d)virtual139)the standard audio sampling rate in a PCM telephone system is _____ khza)2 b)4c)8 d)16140)when human voice and music are transmitted, the tyoe of communication employed is known asa)radio telegraphy b)radio telephonyc)audio frequency d)wired radio141)when one channel picks up the signal carried by another channela)echo b)party linec)cross talk d)cross link142)the circuit connecting a subscriber station with the line terminating equipment in a central office is calleda)local loop b)tie linec)trunk d)subscriber loop143)________ refers to the percentage of time a circuit or facility is in usea)availability b)trafficc)reliability d)occupancy144)in an ISDN network, the ______ blank provides only OSI layer functions including the electrical and physical termination of the network on the customer premises

a)NT2 b)TE1c)NT1 d)TE2145)ADSL increases existing twisted pair access capacity bya)threefold b)twofoldc)fiftyfold d)thirtyfold146)the 1948 theorem which is the basis for understanding the relationship of channel capacity, bandwidth, and signal to noise ratio is known asa)Reeve’s law b)Shannon’s lawc)Nyquist law d)Hartley law147)what appears to be the practical limit for analog modems over standard telephone networka)19.2 kbps b)24 kbpsc)33 kbps d)28.8 kbps148)digital subscriber line (DSL) refers toa)a connection created by a modem pair enabling high speed communicationsb)a specific length of wirec)a specific gauge of wire used in modern communicationsd)a modem enabling high speed communications149)_______ and HDSL essentially equivalent technologiesa)SONET b)ATMc)T1/E1 d)ETHERNET150)what is the source of limitation on the bandwidth of the public switched networka)local loop b)subscriber linec)telset d)the core network

151)the practical upper limit of length of ADSL isa)18,000 ft b)6,000 ftc)12,000 ft d)36,000 ft152)T1 and _______ refer to the same multiplexing systema)DS-1 b)STM-1c)OC-1 d)STS-1

153)the correct order of fax calls phases is which of the followinga)call set up, pre image handshake, line testing sequence, image transmissionb)call set up, line testing sequence, pre image handshake, image transmissionc)line testing sequence, call set up, pre image handshake, image transmissiond)pre image handshake, line testing sequence, call set up, image transmission154)a gigahertz based coax line is capable of delivering how many time more bandwidth than coppera)2 b)50c)1,000 d)10,000155)what is the bandwidth of the telephone systema)535-1605 khz b)340-15000 hzc)300-3400 hz d)88-108 hz156)which of these is specified by C-conditioning?a)signal to noise ratio b)harmonic distortionc)gain/attenuation distortion d)phase hits157)a long distance trunk line operates as _______ linesa)simplex b)half duplexc)full duplex d)full/full duplex158)pulse spreading is a result ofa)relative delay distortion b)phase impulse hitsc)phase jitter d)amplitude jitter159)which measurement compares signal strength to noise level?a)impulse hits b)attenuation/gain distortionc)signal to noise ratio d)amplitude jitter160)which telephony line impairment is a change in signal amplitude for a short time duration?a)white noise b)interferencec)harmonic distortion d)gain hit161)line conditioning is performed ona)dial up lines b)leased linesc)private lines d)both B and C162)envelope delay distortions a measure ofa)relative time delay across the bandwidth

b)amplitude variations across the bandwidthc)phase variations in signals across the bandwidthd)signal attenuation across the bandwidth 163)D-conditioning define specifications of a)propagations delay variations b)interference limitsc)signal to noise ratio d)amplitude variations164)what is done to a telephone line to tighten gain/attenuation parameters?a)it is replaced with a fiber cable b)it is switched to a different linec)it is conditioned d)it is replaced with new copper lines165) time division multiplexinga)divides packets into audio cells to be placed on the telephone linesb)assigns channels to different frequencies in the transmission bandwidthc)assigns time slots to each channel packet sectionsd)uses asynchronous data transmission only166)what is a disadvantage of time division multiplexing (TDM)a)slower transmission rates b)large packet sizesc)small bandwidth d)more overhead167)what is the purpose of using alternate mark inversions and return to zero encoding data?a)faster digital data transmissionb)assist in clock recoveryc)more efficient transmission of analog datad)reduced susceptibility to noise168)how many channels are used to make up a group level channel frequency division multiplexing?a)600 b)60c)300 d)12

169)ISDN is a)a transport type protocol that uses the plain old telephone systemb)a data link protocol that use HDLC as a basisc)AN integrated syntax network

d)digital interface system170)the US primary rate interface (PRI) data rate is a)1.544 Mbps b)2,048 Mbpsc)192 Kbps d)144 Kbps171)which ISDN block is responsible for converting non-ISDN format?a)TE-2 b)TE 1c)TA d)NT 1172)which type of media is least susceptible to electrical interference?a)microwave b)unshielded twisted pairc)shielded twisted pair d)fiber optics173)what is the composition of a ISDN BRI (basis rate interface)?a)B+2D b)2B+Dc)23B+D d)30B+D174what TELCO parameter limits the type of modem that can be used with a given data rate?a)bandwidth b)attenuationc)line impedance d)noise175)which of these is NOT a currently used method of multiplexing data channels onto a single transmission medium?a)time division multiplexingb)code division multiplexingc)wave division multiplexingd)encrypted division multiplexing