The GDS3710 is excessively restrictive in what SIP numbers can be entered…for no good reason, and it is causing a lot of grief here.
You cannot enter * or # into the SIP number. As it turns out, this is important to be able to do, since we are using system speed dialing to call users and those numbers start with a *. I can think of no good reason that the * and # characters are disallowed.
You cannot use the same SIP number on two different users. We have a need to do this, and the system is needlessly disallowing this. It produces an error message if you try to add the same SIP number to a second account. Why should this be disallowed? In some cases we DO want to use the same SIP number for multiple users, such as when we want the reception desk to screen their guests…so multiple users can have individual entry codes, but their guests (who enter the user #) will be routed to reception.
It would be quite useful to allow follow-on digits after the SIP number. These are digits that are sent once the call is answered. For example, to dial an extension number. This could be entered as 12223334444,5555 for example. This would allow a user to be called on their office phone when they didn’t have a direct dial number and they are located at a distant branch office.
Really, there is no need to prohibit #1 and #2 above. It is perfectly reasonable for multiple users to share one SIP number (such as when the receptionist is screening their guests.) Why prohibit it. I would remove the restriction entirely, or, if it served some purpose then have a checkmark where the restriction can be disabled.