Phone Without HOLD key

I have a set of analogue phones connected to asterisk using an SP2102, which is working very well, but one problem I have is that I have no way of putting a call onto hold to transfer to another phone.

My phones have the usual 0-9, #, * and an R key.

I’m looking for a way to use either the R, # or * key to place a call on hold. Neither of these buttons do as I wish at the moment.

As many automated phone services (e.g. telephone bill payments) require the use of DTMF # and * tones, the R key seemed like the best option, however I read that signalling may be a problem here.

Can anyone offer any advise on how I can make this work, e.g. by pressing * and # in quick succession?

Asterisk can park calls, but not hold them. R may work with the ATA. * and # can be used with Asterisk’s features.conf.

Note R on a modern analogue phone is different from the other keys. It typically generates the equivalent of going on hook for a short time - a hook flash. In the UK that is about 100ms. In the US it is much longer. At least in the UK, R may also short one of the phone wires to ground.

Thanks, I’ve just been reading up on features.conf, and maybe ** in quick succession is the way to go, as that shouldn’t interfere when calling automated systems.