PACTOR Series: PACTOR I - PACTOR II - PACTOR III - PACTOR IV
PACTOR-I is a digital data protocol combining elements of PACKET and AMTOR ARQAutomatic Repeat reQuestAutomatic Repeat Query.
PACTOR-I is used by many groups, including Sailmail for mariners to send and receive emails. It is also used by Ham Radio operators, Governmental and Diplomatic agencies, and even NGO's. PACTOR-I is also used as a Selcall protocol to establish connections with other PACTOR modems. PACTOR-II, III, and IV modems all use PACTOR-I for selcalling.
PACTOR I has 200 BdBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second. rate, Huffman compression technique, uses 2 FSKFrequency-Shift Keying tones with a shift of 200Hz, and true binary data transfer capability. Created by Ulrich Strate (DF4KV) and Hans-Peter Helfert (DL6MAA) in 1990.
Standard PACTOR I:
|PACTOR I FSP||PACTOR I FECForward Error Correction||PACTOR I SELCALL|
FSP = Free-Signal Protocol. The basic idea behind the "Free-signal" (FS) is that the host (e.g. a maritime coast station), advises all clients that at present there is no link in opera- tion i.e. it is free, by transmitting an often repeated special signal. Clients hearing this signal may call.
- Hobby Level Software
- Professional Equipment/Software
Since PACTOR hardware modems are relatively expensive, the WINMOR and ARDOP software modes were developed after PACTOR to give amateur radio operators a means to send email over radio for free. VARA, which is a shareware mode, may have been developed as a lower-cost competitor to PACTOR III with similar transmission speeds, though PACTOR's reliability is said to be better than VARA.
Winlink (formerly RMS Express) is an amateur radio global radio messaging service which can relay messages sent by radio to conventional e-mail servers. Winlink's radio messaging software client is called Winlink Express. Winlink Express is compatible with several PACTOR hardware modems, as well as WINMOR, ARDOP, and VARA. Winlink Express is available for Windows users only (or other x86 operating systems if run with Wine). Linux, Mac, and Raspberry Pi users may use Pat, which is compatible with PACTOR, WINMOR, and ARDOP.