Tuesday, January 13, 2009

Need USB 2.0 to Synchronous/Asynchronous Serial Networking Capabilities?

FarSync Flex USBThe FarSync Flex USB Sync/Async Adapter works with X.21, RS530, V.35, RS449, RS485 and RS232C network interfaces operating at serial line speeds up to 2 Mbits/s. FarSync Flex USB provides as single port and is designed to provide a high performance communications solution for use with TCP/IP and an API for companies who wish to quickly develop their own communications solutions. The API permits HDLC framed and transparent bit stream operation from Linux and Windows. The FarSync Flex software and drivers on Windows and Linux can now support 2 wire RS485 operation. All existing FarSync Flex devices can be upgraded to support RS485. This new RS485 serial support adds line types of 2 wire (half duplex) RS485; multi drop and single ended, with line speeds of up to 512 Kbits/s, and with NRZI, FM1 or FM0 signaling modes.

F-FS4100 FarSync Flex USB Sync/Async Adapter with Linux and Windows Drivers

Tuesday, January 6, 2009

Addressing a Common FireWire Repeater Port Count Question

> What we would like is the:
> FW8-FIO-UB4PRH Unibrain FireRepeater-800 Pro FireWire 800 IEEE 1394b
> Repeater Hub 4 Port
> Assuming (all ports a bi-directional) as we would like 4 output
> devices feeding into
> 1 input device.

Unibrain FireRepeater-800 Pro FireWire 800 IEEE 1394b Repeater Hub 4 Port
Since FireWire is a true peer-to-peer technology, unlike say, the prosaic USB standard, terminology for FireWire repeaters and hubs is a little different. Typically the count on a FireWire repeater hub is the total available ports, since the host computer is considered just another peer level device. In other words, plugging a computer into the FW8-FIO-UB4PRH leaves three available ports left. If you have 5 total devices to connect (including a computer), then you could deploy two of the repeater hubs in conjunction with each other. The following schematic illustrates one such configuration with FW8R1 and FW8R2 representing separate FW8-FIO-UB4PRH units.


FW8R1
-----
HOST --- = p1 |
| p2 = --- DEVICE FW8R2
| p3 = --- DEVICE -----
| p4 = ------------ = p1 |
----- | p2 = --- DEVICE
| p3 = --- DEVICE
| p4 = --- DEVICE
-----|