Use of transponders on the ground

[roundwego]

I thought it would be easy to find a reference to the correct protocol regarding the use of transponders on the ground.
Obviously at SMGCS equipped airports, aircraft transponders should be switched on before pushback/taxi until back on stand but what about airports where no such equipment is used?
My company's procedure at a non SMGCS airport (99.9% of our ops) is to switch it on just before line up and switch it off after vacating the runway but is this "best practice"?
May I ask what is SOP for other airlines?

Would also appreciate if anyone is aware of any published guidance on this subject relating to UK ops. I have waded through the Eurocontrol and CAA sites to no avail.

[Denti]

Our SOP is to leave it on Auto at all times except if told directly by ATC to switch it off (which would be standby, no off setting on the box). Hower, normally on taxy in we change the squawk to 2000, from start of december on to 0000.

On SMGCS equipped airports we should leave the assigned squawk in from the time we receive it until we pulled into the gate, however to be honest most forget to leave the squawk in during taxy in except if we get told to re-squawk the old code, LSZH ground controllers for example are very fast to do that.

[Dan Winterland]

TA/RA on after start scan. Sby on after landing scan. It's tha Auto setting that's important. The equipment whan selected to Auto will provide the info required by SMGCS