Us: Debit Exchange Cds -Circular Date Stamps)

US: Debit Exchange CDS -Circular Date Stamps)
Any members able to explain how these worked, usage please?
Any links, catalogues?

Please show an example of the markings in question. At this moment I am a blind man looking at an elephant.

I am in the same boat as you.
I am guessing a pre UPU accountancy area.

Mr. Richard Frajola.

1c Eagle Carrier used to Germany, 1c blue carrier (#LO2) with red star cancel on 1853 cover from Philadelphia, via New York and by Prussian Closed Mails to Wurttemberg,blue 12 November Philadelphia, PA postmark with overstruck "6" at foot, matching "30" rate handstamp at left, "New York Br. Pkt "23" debit exchange office handstamp, carried by Cunard Line steamer Africa, red Aachen "29/11" transit backsamp (image of back here), PF cert (here), one of ten reported examples of the Eagle Carrier used to Foreign destination, one of two known to Germany, very fine



https://www.rfrajola.com/Oct2021/Nov2021.htm

Belay the request.
All sorted
The 1848 Anglo-American Postal Treaty

Gibbons Stamp Monthly 2018
Author Julian H Jones.

Readers Help Wanted

Figure 18 shows a cover sent via New York
to the Chicago exchange office which was
carried on the Etna and left Liverpool on 29
June 1864. It picked up mail at Queenstown
on the 30th and arrived in New York on 8
August. Nine examples with this circular
'21 CENTS' mark are known used between
6 June 1864 and 16 March 1865. All are on
covers and were sent via Allan or Inman
line ships from England. The mark is not
recorded in the English or Scottish proof
books. The author would really like to hear
via the Editor of GSM from any reader who
has a cover with this mark in their collection
in the hope of identifying where it was used.