SG-2000 MANUAL
27
The SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA
©1995, SGC, Inc.
TEL: (206) 746-6310 FAX: (206) 746-6384
9.2
External Modem, Weatherfax and High Seas Direct™
Connector J301 is used to connect the SG-2000 to an external modem. Details are shown
in the diagram below:
1 2 3 4
J-301
Pin 1: Audio input (600 ohm impedance) (From modem audio out)
Pin 2: Ground
Pin 3: Audio output (600 ohm impedance) (To medem audio input)
Pin 4: Push-To-Talk line (PTT line on modem if available)
SG-2000 Rear panel
connections for external
modems, Telerex™ and
Weatherfax
Weather fax modems: Connect Ground from modem to Pin 2 and audio input to
modem to Pin 3 of J-301. (Weather fax modems may also be connected to the external
speaker jack.) See Appendix for High Seas Direct connections. See page 61 for
connection to ALE controller and serial devices.
9.3
Continuous Duty Ratings
If you are planning to use your radio for intermittent voice communications,
continuous duty ratings are of no consequence. However, if you are planning to
transmit for long periods of time on a frequent basis, you should consider the duty cycle
and continuous ratings of components, ordering heavy duty cooling options if
necessary.
Duty cycle is a simple concept. If you are dealing with speech and you will be
transmitting about one quarter of the time, then the duty cycle of equipment is about
50%. However, if you are planning extended broadcast of information, speaking or
sending hours of information such as using a transceiver in the ARQ data transmission
mode, then continuous duty ratings are required.
All SGC equipment is conservatively rated. We use commercial service ratings for all of
our equipment and make continuous service available upon request. Continuous
Service is primarily a matter of adding additional cooling to a unit, as heat is the culprit
in most component failures when equipment is used in continuous service.