| Heading and notes: | No form number. TELEGRAM at top (centered except for EO-1F). | 
| Message area: | Blank. | 
| Reverse side: | Blank. | 
| Colours (text & envelope): | Red on cream or light brown. | 
| Size of envelope overall: | 80 × 136 mm. | 
The design for the first ordinary rate delivery envelope followed the format for the Interim envelope issued by New South Wales (NI-EO-1). It simply eliminated the printed seal on the flap.
It appears however that during the later years of the Interim period - in a prelude to the Establishment period - the design based on the NSW model was accepted for Commonwealth purposes and printing began. Printing of this format continued possibly into the Brown years (post-1922).
There were at least three printings up to about 1920 - in Queensland, in New South Wales and in Victoria. At first glance, these printings all look the same but on closer inspection, the details are seen to be different.
|  | AE-EO-1A Qld. Used at Telegraph Branch, Queensland 19 March 1915. See detailed scans elsewhere. 
 
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The New South Wales format.
|  | AE-EO-1A NSW. Used at Wagga Wagga on 2 July 1920. Characteristics: 
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The Victorian format.
|  | AE-EO-1A Vic. Used at Geelong (3 February 1922). Characteristics: 
 Also known used at White's Flat, SA (no date) and Dubbo, NSW possibly in 1923. | 
Subsequent variations.
|  | AE-EO-1Ba. Used at Maylands, SA. Characteristics: 
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|  | AE-EO-1Bb. Used at Southport, Qld (17 December 1925) Characteristics: 
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|  | AE-EO-1Bc. Used ordinary rate delivery envelope. Characteristics: 
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| IMAGE NOT PRESENTLY AVAILABLE. | AE-EO-1C. Characteristics 
 
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|  | AE-EO-1D. Used at Ivanhoe, Victoria. Characteristics: 
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|  | AE-EO-1E. Characteristics: 
 This envelope must have been stored against the front of a window envelope for some time before it was used. The clear impression of the window belies the fact that this is really an opaque envelope. | 
|  | AE-EO-1F. Used at Chiltern, Vic (has accompanying form) Characteristics: 
 
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More examples are required to finalise this classification.
Details of use and rarity.
| Form sub-number | Schedule number | Earliest recorded date | Rarity rating | 
| EO-1A | None. | 23 July 1924 at Homebush, NSW. | C | 
| EO-1Ba | None. | R | |
| EO-1Bb | None. | 17 December 1927 at Southport, Qld. | R | 
| EO-1Bc | None. | R | |
| EO-1C | NSW Stores Stock No. 455. | R | |
| EO-1D | None. | 2 June 1924 at Petersham, NSW. | C | 
| EO-1E | None. | R | |
| EO-1F | None. | 19 May 1930 at Chiltern. | C |