Which Modem Model?

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Which Pactor Modem to Buy?
There are three models of Pactor II/III Radio Modems from which to choose; The SCS PTC-IIusb, PTC-IIPro, and the PTC-IIex. From a Sailmail or Winlink viewpoint, the primary differences between these three are:

Designed with cruisers needs in mind, the PTC-IIusb connects directly to a computer's USB port, and gives you computer-controlled frequency selection. $200 less expensive than the PTC-IIPro.

The PTC-IIPro design meets the needs of today's digitally oriented high-tech Amateur Radio Operators. With the ability to add up to two 2330 Packet DSP modules the PTC-IIPro in effect becomes three modems in one box; an HF Pactor modem, and two VHF Packet modems. With at least one 2330 installed and simultaneously connected to both a HF and VHF transceiver the PTC-IIPro can be used as a VHF Packet to HF Packet/Pactor Gateway station.

The PTC-IIex is does not provide computer-controlled frequency selection; however, DockSide Radio has found what we consider an acceptable way to achieve frequency control by bundling selected third-party cables and adaptors together with the PTC-IIex modem into "Kits" for certain radio models. The benefit of these PTC-IIex-based kits is that they sell for $200+ less than the single-solution PTC-IIusb-based kits while providing similar functionality. On the downside, the PTC-IIex kits are a bit more complicated to connect and configure than are the single-solution PTC-Iiusb kits, and the third-party components are not covered by the SCS five(5) year manufacturers warranty.

All three modem models incorporate the same digital signal processing circuitry and have the same uncanny ability to deliver 100% e-mail copy when you cant even hear the signal.

Computerized Frequency Control - How Important is it?
In a word...important. Currently there are twenty (20) shore-side Sailmail stations worldwide. Each of these stations scans from five to twelve frequencies, making a maximum total of almost 200 frequencies to be monitored. So just how important is the ability to control the radio with your computer? The short answer is it's really important - Here's why:

The transmitting frequency and station call sign must be associated with each other in order for radio-based e-mail to work. AirMail must send a connect request to a Sailmail network station using both the correct station call and frequency. Radio memory is organized serially, beginning at location 00 and counting up, so the programmed list of frequencies becomes one long onerous series of frequencies & station labels.
The Pactor II/III Radio Modem/SSB system makes an excellent weather FAX (WEFAX) receiving system using the GetFAX/ViewFAX applets that run under Sailmail/AirMail. GetFAX supports 59 additional frequencies for 14 WEFAX stations worldwide, This, added to the 88 Sailmail frequencies, makes a total of about 123 Sailmail & WEFAX frequencies to keep current and access.
For safety while underway, it is important to keep the ships systems as simple to use as practical while maintaining necessary functionality. Pushing one single computer key (up/down arrow), to select a station and a frequency is both easier and more error-free than hunting for your printed radio channel guide, looking up the correct radio channel, and turning channel selector knobs to the appropriate channel number. If the desired station can't be heard on the selected frequency, then the whole process of manually looking up a different station/frequency must be repeated again, and again, until a station is heard. Yes, the manual look-up system can be used, but it's a "pain", and with any kind of sea running is totally impractical.

The Solution:
Computer control of the radio can be achieved with all three modem models. Controlling a radio through the PTC-IIusb or PTC-IIPro using the Airmail program is simple two-step process; plug in a cable, configure the Airmail program... you're done.

If the SCS PTC-IIex is chosen, computer control of the radio can be implemented through a direct connection to a computer serial port with a serial cable, if you have an Icom M802, a specially made cable if you have an Icom M700Pro or M710, or a ISB/CI-V adaptor kit if you have an Icom Ham "rig". Most cruisers, however, have a laptop computer on board, and most laptop computers sold today have only USB ports, no serial port. The PTC-IIex radio control solution requires that your computer have two serial ports available; one to connect to the SCS PTC-IIex, and one to connect to the radio. It's possible to add one or two serial ports by purchasing a USB to serial adaptor (DockSide Radio occasionally has USB/Serial adaptors for sale). If a second serial port is available, a custom cable can be fabricated to control the Icom M-700Pro, M710, & M710RT. An Icom M-802 can be controlled with a standard off-the-shelf serial cable available from most computer stores.