Using An External Modem - Compaq 1610 Reference Manual

An external modem can be used when you do not have a built-in
modem in your handheld PC or when you do not have a PC Card
modem. An external modem can also be used when you want to
consume less battery power than using other modem alternatives.
To use an external modem, you must provide a null-modem cable
and a 9-pin to 25-pin adapter. Follow these steps to connect the
external modem to the handheld PC:
1. Connect your C-Series to external power, then connect the
auto-sync cable to your handheld PC, leaving the 9-pin end
(the end that usually connects to your computer) open.
2. Connect the 9-pin end of the null-modem cable to the open
end of the auto-sync cable.
3. Connect the other end of the null modem cable to the 9-pin to
25-pin adapter. Then connect the adapter to your modem.
4. Connect the modem cable to external power.
When using an external modem with your device, be sure the
modem is turned on before configuring a dial-up connection.
Unlike some PC Card modems, your handheld PC does not
recognize specific types of external modems. Your device
recognizes the external modem only as a generic modem on
COM1.
Using the Modem
Use only a null-modem cable for this connection.