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      TECTIDB  Version 1. 3     3/1/92



TECHNICAL TIDBITS
[Category TEC] 

ALE : Automatic Link Establishment, A Discussion
The following was submitted by Nathaniel McMillian, NTIA/ITS.
Federal Standard 1045 (FS 1045) defines Automatic Link
Establishment or ALE as the capability of an HF radio to initiate
a circuit between itself and another radio without operator
assistance and usually under processor control.  As the Federal
community moves more toward ALE, not only will HF radio
operations become more efficient, but the capability of shared HF
radio resources (or SHARES) will be enhanced. A review of some of
the basic features of ALE will demonstrate its potential.
An ALE radio is designed to continuously monitor an HF network or
networks on up to 100 predesignated channels. Upon detecting an
incoming call, ALE tunes the transmitter, sends a reply to the
caller, and waits for an acknowledgement. Once the
acknowledgement is received, the ALE sounds an alarm announcing
the incoming call, activates the speaker, displays who is
calling, on what frequency, in what mode, and waits for operator
intervention. After the transmission is completed, the ALE units
returns to monitoring the predesignated channels. If the incoming
call is for data traffic, the controller automatically routes the
call to a data terminal without operator intervention. For
outgoing calls, the operator tells the controller the destination
station or stations and the desired mode of operation. The
controller picks the best available preprogrammed channel,
completes all the tuning and handshake work and, when the link is
established, waits for operator intervention. Besides simple
network monitoring and linking, ALE also provides for linking all
stations in a network with a single call; or automatically
responds to a net, or multiple net, collective call.
With ALE, most of the work is efficiently done by the processor,
leaving the operator free to do other things. As impressive as
ALE is today, additional features are under development. These
features include automatic networking, automatic message store
and forward, anti-interference, privacy, automatic relaying, and
automatic networking with other media. RB192-91

FERRITE BEADS AND RADIO INTERFERENCE
"Using Ferrite Beads to Keep RF Out of TV Sets, Telephones,
VCR's, Electronic Equipment, Burglar Alarms and Other" is
available with a SASE from the Stanislaus Amateur Radio
Association, P.O. Box 4601, Modesto, CA 95352. Many of us have
been bedeviled with HF-SSB interference on EOC telephone lines
from RACES, CAP, MARS and other transmitters. If you have or have
had similar problems, this handout has a wealth of information
for serious troubleshooters. (Thanks to the SARA, N6OCV, and
Palomar Engineers. ) RB 026