oid1 OBJECT IDENTIFIER ::= {iso standard 2345 modules (0) basic-types (1)}
oid2 OBJECT IDENTIFIER ::= {joint-iso-itu-t ds(5)}
oid3 OBJECT IDENTIFIER ::= { oid2 modules(0) }
oid4 OBJECT IDENTIFIER ::= { oid3 basic-types(1) }
oid5 OBJECT IDENTIFIER ::= { 2 5 0 1 } -- equals oid4

在“&”之后使用大写/小写在语义上很重要。

MY-SIMPLE-CLASS ::= TYPE-IDENTIFIER

MY-CLASS ::= CLASS {
  &id OBJECT IDENTIFIER UNIQUE,
  &simple-value ENUMERATED {high, low} DEFAULT low,
  &Set-of-values INTEGER OPTIONAL,
  &Any-type,
  &an-inform-object SOME-CLASS,
  &A-set-of-objects SOME-OTHER-CLASS
} WITH SYNTAX
    {   KEY           &id
      [ URGENCY &simple-value ] -- Optional
      [ VALUE-RANGE &Set-of-values ]
      PARAMETERS &Any-type
      SYNTAX  &an-inform-object
      MATCHING-RULES  &A-set-of-objects
   }

my-object MY-CLASS ::= {
    KEY { ....... }
    URGENCY high
    VALUE-RANGE { 1..10 | 20..30 }
    PARAMETERS My-type
    SYNTAX defined-syntax
    MATCHING-RULES { at-start | at-end | exact }
}

My-object-set MY-CLASS ::= {
                object1 | object2 | object3,
                ...,
                version2-object
}

Message ::= SEQUENCE {
    -- Has to be an OBJECT IDENTIFIER (KEY) from the set:
    key MY-CLASS.&id ({My-object-set}),
    -- Has to be the PARAMETERS for the object with KEY:
    parms MY-CLASS.&Any-type ( {My-object-set} {@key} )
}

变量类型值字段和值集字段不在本参考卡的范围内

通常在 ASN.1 模块中指定值仅用于指示默认值，或用于约束项的范围（例如名称的最大长度）。

defaultOn BOOLEAN ::= TRUE
maxAge INTEGER ::= 120
bitmask BIT STRING ::= ‘7FFF’H
defaultBytes OCTET STRING ::= ‘010F’H
placeholder NULL ::= NULL
defaultID OBJECT IDENTIFIER ::= {joint-iso-itu-t country(16) us(840)}
defaultPrice REAL ::= 9.99

Item          ::= SEQUENCE {
   id               CHOICE { -- id alternatives - code, url or color
                      code   INTEGER (0..MAX),
                      url    VisibleString,
                      color  ENUMERATED { black, blue, ... ,-- extended
                                          green, red}
   } DEFAULT code:9999,
   quantity         INTEGER {single(1), dozen(12), crate(36)},
   options          BIT STRING DEFAULT '101100011'B,
   unitPrice        REAL ( 1.00 .. 9999.00 ),
                    ... , -- 此行以下允许扩展名
   [[ isTaxable BOOLEAN DEFAULT FALSE ]], -- 在 v.2 中添加到项目
   [[ voltage INTEGER (110 | 220) OPTIONAL ]] -- 在 v.3 中添加
}
defaultItem Item ::= { -- 这是上述类型的值
   id code : 1,
   quantity single,
   options '0'B,
   unitPrice 1.99
}

ListOfNumbers ::= 整数序列
firstPrimeNumbers ListOfNumbers ::= {1, 2, 3, 5, 7, 11, 13, 17}

name1 UTF8String ::= “Joe” -- 还可以容纳国际字符
phone NumericString ::= “8885551212”
text IA5String ::= “任意文本 - 带标点符号，没问题。”
name2 VisibleString ::= “Joe” -- 不带控制字符的 US ASCII

myDay DATE ::= “2012-01-31”
noon TIME-OF-DAY ::= “12:00:00”
noonMyDay DATE-TIME ::= “2012-01-31T12:00:00”
lunchtime DURATION ::= “PT1H” -- 一小时吃午饭

这是用于限制字符串大小的值表示法的常见用途， 特别是如果将在多个地方使用相同的值：

upperSize INTEGER ::= 64
VisibleString (SIZE (0..upperSize) )
ItemList ::= SEQUENCE (SIZE(0..upperSize)) OF Item

所有定义引用名称（类型、值、类定义、对象定义、对象集）的赋值都可以给出一个虚拟参数列表。 这里我们有两个虚拟参数 - normal-priority 和 Parameter。

Invoke-message {INTEGER:normal-priority, Parameter} ::=
SEQUENCE {
component1 INTEGER DEFAULT normal-priority,
component2 Parameter }

现在我们将消息定义为两种可能性的选择，它们仅在默认优先级和要使用的类型方面有所不同：

Messages ::= CHOICE {
   first Invoke-message { low-priority, Type1 },
   second Invoke-message { high-priority, Type2 },
   ... }

Messages ::= CHOICE { -- 这就是上面扩展的内容
   first SEQUENCE {
     component1 INTEGER DEFAULT low-priority,
     component2 Type1 },
   second SEQUENCE {
     component1 INTEGER DEFAULT high-priority,
     component2 Type2 },
   ... }