>> I'd use <idno> for the telegraph number -- it's not really clear what
>> "formal cataloging system" might mean, but I use it for 19th-century
>> despatch numbers, which are no more formal than telegraph numbers.
>> I'd use @style with CSS for the rendering too; it keeps your TEI clean,
>> and it will actually translate nicely to HTML when you need to render.
> The attribute n might also be usable for this purpose, assuming that this is
> the name or number of the telegram itself, functioning in the same way as
> (for example) a chapter number.
Thanks, Martin and Lou! These are very helpful confirmations & suggestions.