| External Tone Decoders | |||
| Product Code 28 | |||
| Unit | Voltage | No of Reeds | Tone Freq |
| D | 2 | 0 | 0 |
| Type 99 Decoder | 12 VDC | None | None |
| T | 4 | 2 | 4 |
| Type 90 Decoder | 117 VAC | 2 Reeds | 590 Hz |
| S | 4 | 5 | |
| Digital Decoder | 4 Reeds | 1500 Hz | |
| V | 6 | ||
| Solid-State Type 99 | 2805 Hz | ||
| Manuals | |||
| Maintenance Manual (Green) | |||
| Digit 1 | |||
| D | LBI3839 | DF5035 | |
| S | LBI4035 | DF5036 | |
| T | LBI3684 | DF5031 | |
| V | LBI4875 | DF5035 | |
| Options | |||
| 4063 | LBI30283 | ||
| 4065 | LBI4875 | DF5035 | |
| 4066 | LBI4875 | DF5035 | |
| 4068 | LBI30397 | ||
| 4074 | None | ||
| 4075 | None | ||
| 4092 | LBI3839 | DF5035 | |
| LBI3684 | DF5031 | ||
| LBI4875 | DF5035 | ||
| 4093 | LBI4785 | DF9033 | |
| 4094 | LBI3839 | DF5035 | |
| LBI3684 | DF5031 | ||
| LBI4875 | DF5035 | ||
| 4096 | LBI3839 | DF5035 | |
| LBI3684 | DF5031 | ||
| 4097 | LBI4353 | ||
| 4101 | LBI4035 | DF5036 | |
| 4102 | LBI4035 | DF5036 | |
| 4103 | LBI4035 | DF5036 | |
| 7468 | None | ||