1. Introduction
30
Professional Firmware important features:
1.7.1
PACTOR-III
PACTOR-III is a third generation HF protocol building on latest developments in 2-
dimensional orthogonal pulse shaping, advanced error control coding, and efficient source
coding. Due to the advanced signal processing methods applied, PACTOR-III provides
outstanding performance under poor and moderate signal conditions. As PACTOR-III also
achieves very high throughput rates under good signal conditions, it is well-suited to HF
channels with good SNR and low signal distortion as well. During the development of
PACTOR-III, high importance was attached to compatibility with ordinary SSB transceivers
(using standard 2.2-2.4 kHz wide IF-filters). Therefore, PACTOR-III can achieve its maximum
speed with using unmodified, common SSB transceivers. The occupied bandwidth is around
2200 Hz.
Thus PACTOR-III is the ideal means of fast and reliable data communication over (the
sometimes difficult medium) HF-radio. The new protocol is fully backwards compatible to
existing PACTOR-I/II networks.
The properties of the PACTOR-III protocol summarized:
x
Under virtually all signal conditions, PACTOR-III is faster than PACTOR-II. Under
average signal conditions a speed gain by a factor 3x to 4x is achieved, under very
favourable conditions the speed improvement can exceed 5x.
x
Maximum data throughput (without compression) greater than 2700 Bit/sec, around 5200
Bit/sec if PMC (online text compression) is applied.
x
PACTOR-III is at least as robust as PACTOR-II under extremely poor signal conditions.
x
Maximum bandwidth only about 2400 Hz.
x
Low crest factor (high mean output power).
x
High spectral efficiency – PACTOR-III makes very good use of the bandwidth.
x
Fully backwards compatible to existing PACTOR-I/II networks.
1.7.2
PACTOR-IP-Bridge
The PACTOR-IP-Bridge (PIB) is a new Network-Integration-Protocol developed by
SCS
. The
dominant protocols of the Internet like TCP/IP, as well as the Point-to-Point Protocol (PPP),
which have become standard for establishment of links between Internet applications, are
combined with the PACTOR modes. The result of this intelligent protocol combination is a
data transparent and relatively fast Internet access via HF-radio using standardized user
interfaces. The PTC appears to an attached PC as if it were a Hayes compatible "telephone
modem”. The PTC locally takes over both the complete PPP and TCP/IP handling. Except for
a minimum fraction of protocol overhead, the physical PACTOR link only carries useful data.
The huge amount of overhead of the TCP/IP and PPP protocols (which are designed for
broadband wired links) is reduced to the absolute minimum required. By locally carrying out
the PPP protocol between the PC and the PTC a further decisive advantage arises: Because of
the very short timeouts, PPP used to be nearly impossible over slow communication channels
with relatively large delays. Timeout problems are now solved by the PACTOR-IP-Bridge.
Summarizing the qualities of the PIB:
x
TCP/IP-transparent and relatively fast Internet-access via HF-radio
x
Internet-services accessible via PACTOR, e.g. E-Mail (SMTP/POP3), FTP, HTTP, ...
x
Up to 4 Internet channels ("sockets") over one physical PACTOR link
