Clear-Com PL-PRO EF-1M, Инструкция по эксплуатации

Страница: 13 / 55

E F - 1 M I N T E R F A C E 2 - 5
Because of the EF-1M’s low profile and compact size, it can function either as a
stand-alone device, or it can be mounted on utility rack shelves. Up to three units will fit
horizontally in one-rack unit (1RU) of space and will offer sufficient vertical clearance to
accommodate a variety of mounting methods. While the EF-1M may be used as a
single-ended 4-wire-to-party-line interface with excellent results, it is uniquely equipped
to work in point-to-point pairs. Much of the discussion in this manual address the issues
of operation in this latter mode.
Due to the superior nulling capability of the EF-1M, more than a single pair of EF-1M
units can be used to link various locations to a single channel.
As an example consider the following scenario: The three Channel A ports of an MS-232
main station are each connected to an EF-1M. (For an illustration, see Figure 4.)
Each of those three is in turn connected to a fiber-optic modem and sent through fiber to
another fiber-optic modem, EF-1M unit, and party-line system at the three remote
destinations. All four locations are now sharing the same channel, linked through fiber,
with a total of six “nulls” on the channel. While the nature of 2-wire to 4-wire hybrids
may limit the maximum number of external 2-wire party lines that can be combined, six
EF-1M units on a common channel, properly nulled, should generally provide a stable
system.
Because the EF-1M will be used with a wide variety of third-party systems and devices, it
is not possible to address all the variables of setups and transmission methods. The key
Because of the EF-1M’s
low profile and compact
size, it can function as a
stand-alone device, or it
can be mounted on
utility rack shelves.