The main distinctions amongst the formats are:
    
      
        | Format: | Position of Authority | Form number | Other feature | 
      
        | 20A | Logo and TELECOM between TELEGRAM and window | TX 65 | No schedule number | 
      
        | 20B | Logo and TELECOM between TELEGRAM and window | TX 65 | Schedule number on left or both sides.
 | 
      
        | 20C | TELECOM centered under the window. | TX 65 | Legs of M are straight. No schedule number
 | 
      
        | 20D | TELECOM centered under the window. | TX 65 | Legs of M are splayed. Schedule number at right.
 
 | 
      
        | 20E | TELECOM centered under the window. | TX 65H | Legs of M are splayed. Schedule number at right.
 | 
      
        | 20F | TELECOM centered under the window. | TX 65 (3/83) | Legs of M are splayed. No schedule number
 | 
      
        | 20G | Logo and TELECOM centered under the window.
 | TX 65 | TELEGRAM is boxed. New word - EXPEDIATE - at beginning of slogan.
 | 
    
     
    
      
        | AT-EO-20A. |  | 
      
        |  |  | 
      
        | Characteristics: 
            TELEGRAM is 47.5 mm long;large deep blue security pattern printed diagonally andevery second line emphasised.
   | AT-EO-20A (reverse side). Characteristics: 
            flap is semi-rectangular and narrow (34 mm);no schedule number. | 
      
        | AT-EO-20B |  | 
      
        |  
 |  | 
      
        | EO-20Ba and EO-20Bb - both have the same format as shown above for the front and for the reverse side. Printed in 1976.
 | 
      
        | Characteristics for both AT-EO-20Ba and 20Bb: 
            TELEGRAM is 49 mm long; blue weave security pattern printed  in vertical and horizontal format;security pattern has OLYMPIC logo in a box withtwo bevelled corners.
 |  AT-EO-20Bb.
 Two schedule numbers - each printed under the flap on opposite sides.
 Security pattern printed in light blue.
 | 
      
        |  AT-EO-20Ba.
 Schedule number on left side only.
 Security pattern printed in mid-blue.
 | 
      
        | AT-EO-20C. |  | 
      
        |  Front.
 Used on 19 March 1987 at Zillmere, Queensland.
   |  Reverse side showing no printing under the flap.
 Characteristics: 
            TELECOM AUSTRALIA reference moved to under the window;logo omitted for this and all subsequent formats;no schedule number on either side under the flap;blue weave security pattern printed  in vertical and horizontal format;security pattern has unboxed OLYMPIC logo like AT-EO-20D.   | 
      
        | AT-EO-20D. |  | 
      
        |  Printed in 1976.
 |  AT-EO-20D (reverse side showing details under the flap).
 | 
      
        | Characteristics: 
            TELEGRAM is 45 mm long and M has splayed legs;large blue security pattern printed diagonally;printing in  light blue. | AT-EO-20D (reverse side). Characteristics: 
            security pattern has unboxed OLYMPIC logo;only one schedule number and it is printed on right under the flap;has same OLYMPIC logo printed under the flap at the left.   | 
      
        | AT-EO-20E. | AT-EO-20F. | 
      
        |  Printed in 1976.
 |  Printed in March 1983.
 
 | 
      
        | Characteristics: 
            form number changed to TX 65H;TELEGRAM is 45 mm long and M has angular legs;large blue security pattern printed diagonally(same as for EO-20Ae) and with unboxed OLYMPIC logo;
schedule number is printed at right under the flap but the left side is blank. | Characteristics: 
            form number changed again to TX 65 (3/83);TELEGRAM is 44 mm long and M has angular legs;medium blue security pattern printed vertically and with no printed logo;no schedule number;THE reverse side continues the inscription used on THE REVERSE SIDE OF all envelopes from EO-20A onwards:TO EXPEDITE DELIVERY ADDRESS TELEGRAMS
 TO A TELEPHONE OR TELEX NUMBER.
 
 | 
      
        | AT-EO-20G. |  | 
      
        |  Printed in February 1987.
 
 |  | 
      
        | Characteristics: 
            form number is TX 65;TELEGRAM is boxed;light blue small dots security pattern printed vertically and horizontally;schedule number under flap is 71174 2/87. | Reverse side of the 1987 envelope incorporating a special new word!!!!! Flap is rectangular and the schedule number is under the right side of the flap. | 
    
     Details of use and rarity.
    
      
        | Form sub-number
 | Schedule number | Earliest recorded date | Rarity rating (used)
 | 
      
        | EO-20A | None. |  | R | 
      
        | EO-20Ba | SCH. A.T.B. C5948 | 26 August 1987 at Apsley (?) 4034, Queensland. | R | 
      
        | EO-20Bb | SCH. A.T.B. C5948 and SCH. A.T.B. 6109-75.
 |  | R | 
      
        | EO-20C | None. | 19 March 1987 at Zillmere, Queensland. | R | 
      
        | EO-20D | SCH. C. 8551/76. | 20 October 1984 at Hobart. | R | 
      
        | EO-20E | SCH. C. 8551/76. |  | R | 
      
        | EO-20F | 3/83 |  | R | 
      
        | EO-20G | 71174 2/87 |  | R |