Differences, switch and terminal server

[Brad Johnson]

We have a building system connected via a Digi ConnectPort TS8. It links 8 IP-based devices back to the network. I always thought terminal servers were essentially standalone mini computers used to connect things like serial devices back to the network, a box with serial and parallel ports for connecting non-ethernet enabled devices back to a primary/master system. In this case, however, the Digi is physically configured like an ethernet switch - a simple black box with nine ethernet jacks, eight for device connectivity and one for ethernet. That implies it's functionally equivalent to an 8-port switch but there has to be a significant different, especially given the $1000+ difference in price. Can those in the know school me, please?






Brad

[charby]

You work for a university, right?

Don't you have an IT department that handles this? I know in my 13 years with Iowa State, that anything behind the wall jack in rooms was handled by IT/Telecom because they provided that service and they managed the switches.

From the wall jack to say various computers, peripherals, or equipment, it was on the dept IT guy or lab manager. I was that IT guy for a couple departments, and I used unmanaged switches for office networks.

[Brad Johnson]

You work for a university, right?

Don't you have an IT department that handles this?

We do, but I want to know because... I want to know. As a building manager it's advantageous to know how the building and infrastructure systems work, even those out of my direct control.

Brad

[charby]

Simple answer.

Looks like the one you are asking about is a managed switch, where different types of traffic can be controlled, and ports shut off/limit speed as needed. Accomplished by remotely accessing the switch via a remote terminal.

A switch doesn't do that, it lets everything through.

[RocketMan]

A terminal server provides serial connectivity to Ethernet.  In other words, it allows serial RS-232, RS422 or RS-485 connections to Ethernet.  If you have a device that has only serial connectivity, you can use a terminal server to connect it to an Ethernet network.

[Nick1911]

Brad, your understanding is correct.

In this case, the particular product is just using RJ45 connections for the serial ports.  They then sell you cables to interface with various serial devices and standards.  For instance: https://www.digi.com/products/models/76000238

This gives the physical appearance of a switch, but they are just reusing the same physical connectors normally used for ethernet.

[Brad Johnson]

Brad, your understanding is correct.

In this case, the particular product is just using RJ45 connections for the serial ports.  They then sell you cables to interface with various serial devices and standards.  For instance: https://www.digi.com/products/models/76000238

This gives the physical appearance of a switch, but they are just reusing the same physical connectors normally used for ethernet.

Ah, okay. That clears it up, along with most of the follow up questions I had, too. Thanks!

Brad

[lee n. field]

A terminal server provides serial connectivity to Ethernet.  In other words, it allows serial RS-232, RS422 or RS-485 connections to Ethernet.  If you have a device that has only serial connectivity, you can use a terminal server to connect it to an Ethernet network.

Outside of manufacturing and industry, where expensive legacy stuff can hang on for a really long time, is serial used much?

[Brad Johnson]

Outside of manufacturing and industry, where expensive legacy stuff can hang on for a really long time, is serial used much?

Still a thing in some lab, industrial, and test equipment, especially legacy equipment.

Brad

[RocketMan]

Outside of manufacturing and industry, where expensive legacy stuff can hang on for a really long time, is serial used much?

There is still some old school serial hanging around, but there is less of it every day.  Most laptops and desktop motherboards no longer include DB-9 RS-232 serial connectors.  And DB-25 serial setups are just plain gone.
Just about everything these days is USB, which is really just the latest and greatest version of serial communication between devices.  Much faster and far more flexible.  USB is Universal Serial Bus, after all.

We were still using RS-232 and RS-422 serial in some HP servers and controls at the Target RDCs where I worked before retiring a few years ago.  Most of that equipment was so old and obsolete that spare parts were impossible to find.  And yet it ran the main sortation system in the last building I worked in.  We had several terminal servers of the sort you pictured that connected equipment to the production LAN.  Even those terminal servers were obsolete at that time.
According to a former cow-orker I ran into at the grocery store, at this time last year they were still using those old servers to run the sorter.  They might still be in service for all I know.