The phrase "a separate number" is correct and usable in written English.
It can be used when referring to a distinct or individual numerical value that is not combined with others.
Example: "Please provide a separate number for each item on the list to avoid confusion."
Alternatives: "an individual number" or "a distinct number".
In fact, having a separate number for walkie-talkie calls is actually a perk.
Skype, for instance, uses a separate number and service and cannot be used for calls to emergency services for instance.
It's like the one on a BlackBerry, except that this one even has arrow keys, modifier keys (like Ctrl and Alt), and a separate number pad.
Chase has helpfully set up a separate number, (866) 550-5705, to take customers of Chase, EMC Mortgage and Washington Mutual straight to a loan modification specialist.
In contrast, the disclosure did not offer a separate number of national security complaints, suggesting that some were not followed up with an assessment.
As it happens, Mrs. Vanderbilt was deserting her house at 666 Fifth Avenue, which she sold for $1.5 million, and it may have been she who selected a separate number for the maisonette — 666 Park Avenue.
Prior to the 2002 season, Atlantic subtropical storms were either not named or given a number from a separate numbering list than tropical cyclones.
In the intervening years of 1975 2001, subtropical storms were either named from the traditional list and considered tropical in real-time, or used a separate numbering system.
This alternative requires the use of a separate numbering file for the residues, which can be included in the pipeline.
The President's plan for an entirely separate number may offer greater protection, but the reality is that unbridled partisanship puts its passage in doubt.
The form includes the ticket's serial number and a separate serial number from a validation slip from the lottery machine.
