[mythtv-users] Frontend USB to TV RS232 serial?

[Brian Wood]

On Monday 03 August 2009 16:18:36 mythtv at derdev.com wrote:
> On a frontend without any available serial ports (RS232) and plenty of
> available USB ports, is there an easy/obvious solution to connect the
> frontend to an HDTV's RS232 serial port for power on/off control?
>
> I see lots of USB to Serial converters but they don't seem to terminate in
> the male serial connection needed to link up to the TV...  Barking up the
> wrong tree here?

I'm not sure what sort of connector you need to connect to the TV. Most 
USB-to-serial converters have a DB-9M. If your TV has a DB-25F connector, 
adapters are readily available.

DB-9 and DB-25 are the only standards for RS-232 connectors I'm aware of, 
unless you count the old Apple round serial connector, or some of the 
RJ "modular" connectors.

> Also, any drivers needed to support such an animal?

I think most of the USB-serial converters are supported by Linux. In some 
cases (like a Direct TV receiver), you have to find an old chip version, but 
if you are using a standard RS-232 you should be OK, the drivers you might 
need are in the kernel.

Devices that use a serial port in a non-standard way, like IR blasters,  
usually can't use the USB-serial adapters. This is not the fault of the 
adapter, but rather due to using the handshake lines of the serial port to 
drive an LED, not something RS-232 is supposed to be doing.

If your machine has PCI-Express 1X slots, there are serial cards available 
that will go into that slot and work fine with Linux.

-- 
Brian Wood
beww at beww.org