I'm setting up a phone system for a small office with two POTS lines and three extensions (likely 2 Snom 300s and 1 Snom 360). Their old (and dying) setup has the two lines connected to a key system, so when a user wants to make a call, he or she picks up the phone, selects a line, and is immediately given PSTN dialtone. In the new system, each POTS line will be connected to an Obi110 which basically converts it to a SIP Trunk and will be configured as a shared line in snom ONE.
I'd like to configure snom ONE to provide as similar a service as possible, so what I'd like to know is how to configure snom ONE (or the phones, if need be) so that when a user goes off hook or presses a line button, the trunk is immediately seized and they get PSTN dialtone. This is important since this office still subscribes to voicemail from the local telco, and they'd like to be able to hear the message waiting stutter tone.
As much as I'd like to, I can't provide voicemail within snom ONE because two channels aren't really enough to support it, and they're under contract with these telco lines until next year. When the contract is up, they'll re-evaluate their options (and probably ditch POTS), but for now, I'd like to get this working this way.
Can anyone shed some light on this? Thanks much.