详细说明：一款经典的数字电话设计资料，内含原理图，C编写的源代码。-digital telephone design information, containing drawings, prepared by the C source code.文件列表: dc550_swa2_hwa2_2-189 .....................\DC550ReleaseNotesSWA2HWA2_2-189.doc .....................\feature_requirements .....................\....................\keypad_templates .....................\....................\................\DC550keypadtemplates1-976.doc .....................\....................\menu_screen_strings .....................\....................\...................\DC550menuaddendumA2-106.doc .....................\....................\...................\DC550MenuScreenStrings_2-054.doc .....................\....................\...........\DC550MenuScreenStrings_2-054_French.doc .....................\....................\...................\DC550MenuScreenStrings_2-054_Spanish.doc .....................\....................\one-touch_messaging .....................\....................\...................\DC550OneTouchAddendumA_2-118.doc .....................\....................\...................\DC550OneTouchMessagingSpec_1-977.doc .....................\....................\product_specification .....................\....................\.....................\DC550ProductSpecification_1-967.doc .....................\....................\ui_design .....................\....................\.........\DC550uiaddendumA2-098.doc .....................\....................\.........\DC550uiaddendumB2-102.doc .....................\....................\.........\DC550uiaddendumC2-188.doc .....................\....................\.........\DC550uidesign2-010.doc .....................\hardware .....................\........\design .....................\........\......\DC550HardwareDesignDocument_2-022.10b.doc .....................\........\......\DC550HardwareDesignDocument_2-022.pdf .....................\........\......\jack_board .....................\........\......\..........\V1_0_Baseline .....................\........\......\..........\.............\DC550_JACK_BOARD_V1_0.DSN .....................\........\......\..........\.............\DC550_JACK_BOARD_V1_0_BOM.TXT .....................\........\......\..........\.............\DC550_JACK_BOARD_V1_0_NET.TXT .....................\........\......\..........\.............\DC550_JACK_BOARD_V1_0_notes.txt .....................\........\......\..........\.............\DC550_JACK_BOARD_V1_0_XRF.TXT .....................\........\......\..........\.............\schematic .....................\........\......\..........\.............\.........\cover_sheet.pdf .....................\........\......\..........\.............\.........\phone_line.pdf .....................\........\......\..........\.............\.........\power.pdf .....................\........\......\..........\V1_1_Final .....................\........\......\..........\..........\DC550_JACK_BOARD_V1_1.BOM .....................\........\......\..........\..........\DC550_JACK_BOARD_V1_1.DRC .....................\........\......\..........\..........\DC550_JACK_BOARD_V1_1.DSN .....................\........\......\..........\..........\DC550_JACK_BOARD_V1_1.NET .....................\........\......\..........\..........\DC550_JACK_BOARD_V1_1.XLS .....................\........\......\..........\..........\DC550_JACK_BOARD_V1_1.XRF .....................\........\......\..........\..........\DC550_JACK_BOARD_V1_1_changes.doc .....................\........\......\..........\..........\schematic .....................\........\......\..........\..........\.........\cover_sheet.PDF .....................\........\......\..........\..........\.........\phone_line.PDF .....................\........\......\..........\..........\.........\power.PDF .....................\........\......\main_board .....................\........\......\..........\V1_1_Baseline .....................\........\......\..........\.............\DC550_MAIN_BOARD_V1_1.NET .....................\........\......\..........\V1_2_Interim .....................\........\......\..........\............\DC550_MAIN_BOARD_V1_2.BOM .....................\........\......\..........\............\DC550_MAIN_BOARD_V1_2.DRC .....................\........\......\..........\............\DC550_MAIN_BOARD_V1_2.DSN .....................\........\......\..........\............\DC550_MAIN_BOARD_V1_2.NET .....................\........\......\..........\............\DC550_MAIN_BOARD_V1_2.XLS .....................\........\......\..........\............\DC550_MAIN_BOARD_V1_2.XRF .....................\........\......\..........\............\DC550_V1_2_changes.doc .....................\........\......\..........\............\DC550_V1_3_notes.txt .....................\........\......\..........\............\readme.txt .....................\........\......\..........\............\schematic .....................\........\......\..........\............\.........\Audio_output.pdf .....................\........\......\..........\............\.........\Band_pass.pdf .....................\........\......\..........\............\.........\COVER.PDF .....................\........\......\..........\............\.........\CPU.PDF .....................\........\......\..........\............\.........\High_pass.pdf .....................\........\......\..........\............\.........\Jack_board.pdf .....................\........\......\..........\............\.........\KEY_PAD.PDF ... ...……