Telephone lines

Disasters affect communities and their populations in different ways. Damaged and collapsed buildings are evidence of physical destruction. Roads, bridges, tunnels, rail lines, telephone and cable lines, and other transportation and communication links are often destroyed. Public utilities (e.g., water, gas, electricity, and sewage disposal) may be disrupted. A substantial percentage of... 

The affiliation is the institution (or institutions) at which the work was conducted. If there is more than one author, use an asterisk or superscript (check the specific publication s style) to indicate the author or authors to whom correspondence should be addressed. Clarify all corresponding authors addresses by accompanying footnotes if they are not apparent from the affiliation line. Telephone numbers, fax numbers, and electronic mail (e-mail) addresses may be included in corresponding author footnotes. 

Touch currents — The victim is touching a conductive surface which is struck by lightning. The current also may travel through power lines, telephone lines, or plumbing pipes to a person who is in contact with an electric apphance, telephone, or plumbing fixture. 

Electric power lines shall be insulated or located away from water lines, telephone lines, air lines, or other conductive materials so that a damaged circuit will not energize the other systems. 

Communications (visual, voice, signal line, telephone, radio, or other suitable type) must be maintained among all persons present (those in the IDLH atmosphere and the standby person or persons). The respirator wearers are to be equipped with safety harnesses and safety lines to permit their removal from the IDLH atmosphere if they are overcome. 

All structures in the work environment should have working, land-line telephones. This ensures that occupants will have a means of communication independent of cellular telephones. Hard-line phones maintain enough electricity within the phone... 

In these case, a lead market is a country that has the ability to change preferences in other markets. In the mobile communication example, a country that is often imitated could have initiated the mobile telephony boom. It just became hip in countries with a dense fixed line telephone net to use mobile phones instead, despite its doubtful additional real benefit. Real benefit of goods and therefore preferences, however, can change with working conditions and lifestyle. Increasing mobility, environmental pollution, and female work participation are global trends that change the preferences of consumers as well as industrial users. 

A trend is the internationalisation mechanism of a nationally preferred innovation. A lead market can also become the lead market when it just happens to have a high benefit from an innovation design because of the special context e.g. a low density of population makes it more profitable to adopt mobile telephones instead of fixed line telephones. 

Although Gruber and Verboven (1999) find a significant negative correlation between mainline penetration and speed of diffusion of mobile telephone in Europe, the penetration rates with mobile and fixed-line telephones correlate within the OECD witli a correlation coefficient of r =0.55 between 1987 and 1995. 

A large percentage of eddy-current inspections are conducted in the field, away from the home base and often in remote or inaccessible locations. Using local telephone lines or mobile phone lines would allow the inspector to beam his data back to the office. In this way highly qualified personnel can be consulted when problems or difficult to interpret results occur. Inspectors no longer need to feel isolated on site. 

In the early 1990s, there were more than 9 x 10 km of fiber-optical telecommunication links in practical use in the United States. In addition, many other countries, notably Canada, Japan, and western Europe, have installed extensive fiber-optic communication systems. There are several transoceanic fiber-based telephone cables. Fibers are in use for intracity telephone links, where bulky copper [7440-50-8] wine is replaced by thin optical fibers. This allows crowded conduits in large cities to carry more messages than if copper wine were used. Fiber optics are used for intercity long-haul telephone links, for interoffice tmnk lines, and have replaced many microwave communication links. 

However, optical fiber communications are not useful only for long-distance communication links. Fiber-optic data links are also used in a variety of short-distance systems, for example in computer—computer links and for internal communications on ships and aircraft. Figure 16 shows some possible appHcations for fiber-optic communications, with respect to length and bit rate. The common carrier appHcations, like telephone links. He to the upper right of the dashed line labeled 100 MHzkm. However, a wide variety of other lower performance appHcations, illustrated to the lower left of the dashed line, are in use or under development. 

Services. These iaclude telephone system FAX machines mail moves deUveries tmcks and vehicle fleet management janitorial and housekeepiag services landscapiag and gardening water treatment and waste disposal reproduction, eg, copyiag machines, blue-line machines, and printing furniture control tool rental and maintenance and instmment rental and caUbration. 

PPIC uses the RCRA/Superfund and Small Business Ombudsman Hotlines as well as a PPIC technical assistance line to answer pollution-prevention questions, access information in the PPIC, and assist in document ordering and searches. To access PPIC by telephone, call ... 

In earlier years, to reach a remote area, where. separate telephone lines had not been laid it was normal practice to rttn them through the same poles as the HT power distribution lines (generally 11-33 kV). This was particularly true of internal communications of the electricity companies for ease of operation and to save costs and time. This commitnication was known as the magneto-telephone system. But the proximity of telephone lines to power lines adversely affected the performance of the telephone lines due to generation of overvoltages (Chapter 20) and eleetrical interferences (conductive and inductive interferences, discussed later) on the telephone lines by the power lines.. Some of these interferenees, particularly system harmonics, had the same frequency as the audio frequency of the telephone lines and alTected their audio quality. 

The running of telephone lines through power lines is long discontinued. They are now run on separate structures within a city and nearby areas at audio frequency (— 0.3-3.4 kHz), and maintain enough distance from HT power distribution lines. They are therefore almost unaffected from such disturbances. Nevertheless, interferences must be kept in mind when installing these lines so that they are out of the inductive interference zone of the power lines. The latest method in the field of communications to avoid disturbances is to use underground optical fibre cables, where possible, as discussed later. Optical fibre cables are totally immune to such disturbances. 

Other than the system harmonics, electrical interferences are also caused by line disturbances, which may be caused by lightning, switching, sparking or a fault. As discussed in Chapter 17, line disturbances occur at very high frequencies but some may coincide with the audio frequency of telephone lines, and cause disturbance in the audio quality of the telephone system. All these disturbances are referred to as inductive interferences. 

In the earlier installations sensitive to such iiuerfercnces (he normal practice was coordination between the generating and power transmission agencies and the authorities of essential services (such as public telephones, defence serv ices and railways), who prov ide (heir (wvn communication systems, lo relocate iheir telephone lines to mitigate this problem at the planning stage,... 

Central Board of Irrigation and Power. India, Interference of power lines with telephone lines Technical Report No. 29. Research Scheme on Power, March (I9S2). 

The world wide facilities for retrieving chemical information provided by the Chemical Abstract Service (CAS on-line) have made it a relatively easy matter to obtain CAS registry numbers of substances, and most of the numbers in this monograph were obtained via CAS on-line. We should point out that two other available useful files are CSCHEM and CSCORP which provide, respectively, information on chemicals (and chemical products) and addresses and telephone numbers of the main branch offices of chemical suppliers. 

Topical applications are housings for TV sets, telephones, fascia panels, hair brush handles, luggage, helmets and linings for refrigerators. 

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