Telex 38109-977 manual Fixed vs. Mobile Requirements, General Overview

the choice, but digital interfaces, such as the SSA424, yield good intersystem transparency. As a result, an initial two-wire purchase can interconnect to an ADAM or Zeus four-wire host later without significant trans-hybrid losses.

Fixed vs. Mobile Requirements

A General Overview

In the age of the portable control room, fixed and mobile requirements in larger systems are surprisingly similar to each other. Within television production vehicles, such as those used for sports and by major networks, all of the intercom forms of communication must be present to produce from small, to very large shows. Notwithstanding, some contrasts between fixed and mobile requirements could include quantities of cameras, belt packs, and IFBs. There are other minor differences, with the majority of them mechanical and weight related. For example, placing a matrix system in a truck might be better served with the more secure DE9 connector rather than the quick disconnect RJ12.

In large television production vehicles, it is common to see 12 to 16 cameras covering a major event. This is typically more than the average television news station where three to six cameras would be more common. Traditionally, cameras were voltage based two-wire, and most of them were not directly compatible with the RTS™ TW intercom. A belt pack was used instead and connected to a SAP1026 or SAP1626 Source Assign Panel to set up the desired conferences.

Along with the increase in number of cameras came the boost in IFB channels in both large mobile and fixed installations. Today, eight to 16 channels of IFB output in a large mobile vehicle are common and have matched the corresponding IFB increase in large fixed installations. The trend toward more IFB circuits in fixed installations has been fueled, of course, by the advent of the portable videotape camera and microwave links that permit multiple reporters to contribute to live newscasts simultaneously.

Curiously, the requirement for vast numbers of belt packs and other two-wire devices has diminished slightly over the years for fixed installations and, to a lesser extent, in large mobile vehicles. One reason for this tendency is that camera intercoms, operating in the four-wire mode, can be attached directly to a digital matrix without an interface. The desired conference channels may be dynamically assembled in the central matrix to establish the required conferences.

Also of note is that the trend toward matrix intercom for mobiles has increased over the last ten years when customarily, trucks would only contain two-wire intercoms with appropriate subsystems. The primary reason for this development is better reliability in matrix systems, as well as, easier reconfiguration of the intercom.

In smaller truck systems, such as satellite and electronic news gathering (ENG) vehicles, a minimal intercom system is often required. These vehicles usually consist of just the cameraman, local director, and talent. The two forms of communication that are required for this kind of remote operation are conference channels and IFB circuits.

IFB used in the ENG situation consists of both local IFB and studio director IFB with the local IFB downstream from the studio IFB. A system configured this way simultaneously allows the mobile director to communicate with the cameraman and IFB. At the same time, the main studio conference channel may be superimposed on the local conference net via either a microwave channel or a telephone interface such as the Telos Link.

The smaller television studio can be similarly equipped. The addition of more control stations, a method of source assignment, and more two-wire belt packs or wireless PL systems is usually more than enough to provide a powerful and easily reconfigurable intercom for the smaller market.

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