I was looking up reciprocity between US & Australian banks for a thread on the US branch. The Australian bank said you can set ATM withdrawal limits "through Telephone Banking on 132 032."
I would have written "through Telephone Banking at 132 032." (Or, more probably, "by calling Telephone Banking at 132 032.") The only US usage I know of dates to the old multiline business phone systems where a receptionist would call you on the intercom line & say "Mr. Smith is on 032."
I looked through the bank's web site & they were rather consistent in the use of "on," so it can't be a typo. For instance: Please contact Customer Enquiries on 132 032 for full details.
So, is this a common way of referring someone to a phone number?

