The 49G has a 10-pin serial connector. Included with the 49G is a 10-wire cable (with 10-pin connectors on both ends, for communication between two 49G's) and a 10-pin to 4-pin adapter (for communication between a 49G and 48 series). It does not include a cable for connecting directly between the 49G and a PC.
The reason the 49G has a 10-pin connector is for additional signals which make it able to directly drive the new overhead projector display.
Although the 49G's 10-pin connector "looks" like the 200LX 10-pin connector, you CANNOT use the 200LX's PC cable. They have different pin-outs, and they are not physically compatible (the 200LX's cable will not plug into the 49G's 10-pin connnector). An for good reason.. if it were plugged into a PC, the 200LX's 10-wire cable would backfeed excessive voltage signals onto the 49G's overhead projector lower voltage bus.
To connect the 49G to a PC requires the standard 48 series 4-wire cable (which is a DB9 to 4-pin connector) and the HP 38 4-pin to 10-pin adapter that comes with the HP 48 connectivity kit (apparently the 38 also has a 10-pin connector). Alternatively, you can buy the new 49G connectivity kit, which I understand is a free accessory (when requested) in Europe. Hopefully HP USA will follow suit.
For more info about the 49G to PC cable, see HP's own Jean-Yves Avenard's 8/26/99 posting in the comp.sys.hp48 usenet newsgroup. Here is the pertinent passage:
"Hello
You can use the HP48 cable and the HP38G adapter that comes in the current HP48 connectivity kit, to connect your HP49 to a PC.
So to summarize...
If you have the HP48 cable (4 pins connector) and the HP38G adapter (4 pins to 10 pins). Then EVERYTHING IS FINE ...
Jean-Yves"
Good Luck, Matt