Using the Ether-Serial Link as a Serial Data Format Converter

1st Thursday, 2011  |  Engineering News, Life at LAVA  |  no comments

Here’s an interesting use for the LAVA Ether-Serial Link: as a generalized serial data format converter.

A quick search on the web shows that people have a variety of needs for converting one RS-232 data format to another, for a variety of reasons, and the solutions are usually cumbersome.

For example, one might want to connect two serial devices that communicate at different, fixed baud rates, or with different parity settings. Without converting the serial data, these devices will not communicate. Some of us remember this problem arising back in the bad old days of dial-up networking, when modems’ settings needed to be matched in parity, baud rate, data bits, parity, stop bits, and flow control settings. When they didn’t match, the communication either failed, or the data was garbled.

But at least you could set the modems to do what you wanted, if you knew what you wanted, knew how to do it, and had access to the modems (no small set of qualifications).

But at other times, the hardware you want to connect cannot be changed: the serial port settings are locked. In these situations, resolving the connectivity problem has usually meant either coding software to to do the specific job needed, or hunting down a piece of hardware to do the conversion (again, just for that specific task).

A case in point: Pete Eirikson, a Commercial Project Manager for Dakota Security Systems, Inc. contacted LAVA for a solution to an existing customer problem. They needed to get a cash register (in 7-bit mode) to communicate with a video server (in 8-bit mode) over serial, where both devices are fixed and not able to change their respective data bit sizes. The solution was to install a Lava Ether-Serial device server on each serial connection and then use our devices to convert the 7-bit data from the cash register to 8-bit data for the Dakota video server.

The Ether-Serial Links are each set in Data Connect mode, with each “pointed” at the other’s IP address and TCP port number. Because the serial ports of the two devices do not need to be set to the same port settings (they can differ on any combination of port settings in fact), the Ether-Serial Links must — and do — manage the translation between ends of the connection.

What this means is that the Ether-Serial Links can provide a transparent means of interconnecting devices with disparate serial port settings. This of course is particularly useful when the devices in question cannot have their serial port settings altered, or not altered to match each other.

A fringe benefit of this method of connecting devices in Data Connect mode is that the devices in question now also can be situated at any distance from each other, from near placement to any distance over the Internet.

In the case of converting 7-bit serial to 8-bit serial for Dakota Security Systems: problem solved.