Using a handset, after a call ends and one party doesn’t return the handset to the cradle, after several seconds the user gets dial tone again.

[EscondidoAdmin]

3CX V18 Update 8 (yes, working on upgrading!), 128SC, Ent, self-hosted. Snom D735 phones.

I’m finding some unexpected behavior. Scenario:

• User A goes off-hook with the handset and calls user B’s extension number (both have snom D735 phones).
• User B answers the call.
• User B hangs up, ending the call.
• User A doesn’t return the handset to the cradle.
• After a few seconds, User A hears dial tone and can make calls by dialing on the keypad.

Alternatively:

• User B calls User A’s extension number.
• User A answers by picking up the handset.
• User B hangs up, ending the call.
• User A doesn’t return the handset to the cradle.
• After a few seconds, User A hears dial tone and can make calls by dialing on the keypad.

I assume this has something to do with the electronic switch hook on the D735 still being off-hook after the call has ended.

Is the dial tone after a call ends in either of the above scenarios a result of a setting on the 3CX or is it a setting in the snom D735?

 

[JohnS_3CX]

These settings are model/brand specific, best to consult Snom directly about such details.

We don't have a setting to control this behavior in 3CX at least.

 

[VoIPTools]

I'm trying to understand what the concern is. The phone is notified that the original call was disconnected and thus assumes, since the user did not hang up for several seconds, that they must want to make an new phone call. Remember dial tone on SIP phones is artificial (unlike old analog phones), so a phone left off-hook is not consuming resources on the PBX. What's the problem/concern?

Why the heck is the user not putting the handset back on the cradle? If they do not want to receive additional phone calls (reason for not putting the handset back) they should change their status appropriately. They can do that easily with a BLF programmed to set the extension to away. That would be a better approach than simply not returning the handset.

 

[EscondidoAdmin]

Hi, thanks for the feedback. A little more on what the request is: we're a city government and at our City Hall, the general public can walk in and use one of a few phones to call a department. Most of the time, after a conversation is over, the person would return the receiver to the public (expected behavior, right?). However, not everyone who comes into city hall acts in an expected way. Transients or other people who may be dealing with various issues can pick up one of the phones and become a nuisance by dialing numbers. I know we can lock the phone down a fair bit to prevent making toll calls but it doesn't seem like we can restrict the phone to making calls to just one extension. Well, short of implementing a hotline, which if used would be circumvented by this operation. The hotline will call the designated number, once that call is over and the caller stays on the line, when they get dialtone again, they're not restricted.

I'm trying to convince people that using a cheap analog set with an ATA is the way to go. Very easy to setup and from my testing, it doesn't have the issue of giving dialtone again if the handset isn't returned to the cradle. IMHO, asking the public to use a desk phone with lots of buttons and a display could be intimidating, an old school 2500 set shouldn't cause anybody concern.