Sources
Primary (OEM)
- Impact Instrumentation, Uni-Vent™ Model 754/754M Operation & Service Manual, P/N 906-0754-02,
rev 1.85N (04/05). Public scans: Internet Archive item
manual_Impact_Uni-Vent_754_Operation_and_Service_Manual; iFixit document library (Impact Uni-Vent 754 Operation and Service Manual.pdf). Sections used: Calibration / Preventative Maintenance Notice; Alarms (PREVENTATIVE MAINTENANCE Alarm, EXTENDED NON-USE/STORAGE Alarm); Communications Port; Transducer Calibration; USER PROGRAMS; §14 Calibration Procedure - Computer Calibration - Software Version 2.7 (communication parameters, files CAL.EXE / Cal754.doc / CAL754.HLP, RTC reset); §15 Circuit Descriptions (80C552, XC7354, NM93CS66N, DS1202, MAX232, lithium cell); parts lists. - Impact Instrumentation, Uni-Vent™ Eagle™ 700 Series 754M Service Manual. Internet Archive item
manual_Impact_Uni-Vent_Eagle_700_Series_754M_Service_manual. §14 Computer Calibration (DOS CAL.EXE key table: F1-F10 and 1-5; Hold/Release behaviour; 4.0 Initializing EEPROM / Resetting the Real Time Clock without the analyzer). -
Impact Instrumentation, Uni-Vent Eagle 754 Operator's Manual (AARC-hosted PDF
02-754OM.pdf): alarm text, CAL mode, calibration label. -
Impact Instrumentation, Uni-Vent™ 754/754M Operation & Service Manual REV. 1.85U (03/11), P/N 906-0754-02, 139 pp, hosted on MedWrench's document CDN for the Eagle 754 equipment page. Newest public revision; same §14 (CAL V2.7) and circuit descriptions, adds part numbers (U10 RTC 055-1202-00, B1 lithium cell 021-0021-00) and notes the Model 100 analyzer may connect by USB.
- Impact Instrumentation, 754(M) Portable Ventilator Test Procedures (DMR/0754(M)/Test, Rev. L),
Internet Archive item
manual_754M_Ventilator_Test_Procedure. §16 EEPROM: protection is enabled during initial computer calibration; §16.1 Real Time Clock Reset: in the Windows program select the Calibration menu → "Reset RTC"; "A reading of 0 or 44 days and 0 hours should be expected". - Impact Instrumentation, Service Worksheet SER/0100-44 Rev G and Rev H, Internet Archive items
manual_Service_Worksheet_Rev_G/manual_Service_Worksheet_Rev_H_Uncontrolled. Records "Real Time Clock Reading ___ Days, ___ Hrs; RTC Battery ___ Volts", an EEPROM block ("Protection Enabled; Real Time Clock Reset; T1 Saved; T2 Saved; Slope Calculated"), and firmware-version-dependent failure codes (Ver 1.83X vs 1.85X). Notes that the Extended Non-Use and Preventative Maintenance alarms "cannot [be] check[ed]" at the factory. - US Army Supply Bulletin SB 8-75-S2 (FY2007), para 1-12, Internet Archive item
manualzilla-id-6031745: Impact "made available a special military FTP site to download operation/service manuals and software for their products" atwww.impactii.com/shared/calsoft.htm(credentials printed in the bulletin). The domain now belongs to ZOLL and the page is not in the Wayback Machine; the bulletin is nevertheless the citation to use when asking ZOLL Medical for the 754 calibration software as a former military customer. - Timeter RT-200 Calibration Analyzer Operation/Service Manual, Internet Archive items
manualsplus_14006andmanual_Timeter_RT-200_Calibration_Analyzer_Operator_and_Service_Manual. Function-code scheme (11-14 low pressure, 21-24 high pressure, 31-34 low flow, 35-38 high flow, 41-43 volume, 45-48 timing) and, on each factory inspection sheet, a one-byte "STANDARD CODE FOR COMPUTER INTERFACE" per function (#12 → 0x20, #35 → 0x46, #36 → 0x41 …) used by the emulator. Neither scan documents the RS-232 command grammar. - ZOLL 731 Series Ventilator Service Manual 906-0731-04-01 Rev. C (2024): the successor product's PM Due alarm (service code 3120) is reset only by the Remote Calibration System after calibration passes; its service link is USB, not RS-232. Confirms the RCS does not cover the 754.
- US patent US8874035B2 (Impact Instrumentation): stockpile-storage diagnostics over a serial/USB connector; the only Impact patent that touches a service data interface. No 754 byte format.
Community evidence
- MedWrench, Impact Instrumentation Eagle 754 forum: threads IMPACT 754 HELP (Spanish-language post describing the "RTC reset" option in the I-Cal software and that the analyzer must be connected for the program to proceed), My Uni-vent error message ("You can just reset the maintenance using the software. rs232 cable, computer and the units powersupply"), Calibration, Calibration Software, Remote Calibration System, Software to connect to a laptop for PM 2000hrs reset, PM & Repair. Consensus: Zoll sells the Remote Calibration System only to military customers; shops that still have I-Cal use Windows XP bench PCs with two COM ports.
- EBME forum thread on the Timeter RT-200 (topics/77269): the RT-200's RS-232C option is a plug-in interface board with DIP switches on connector J-1; no public command documentation.
Component datasheets (behaviour relied on in HARDWARE.md)
- Dallas/Maxim DS1202 Serial Timekeeping Chip: 3-wire interface, 24 × 8 RAM, clock-halt flag, write-protect bit; contents lost without VCC2 backup.
- National Semiconductor NM93CS66 (now Microchip/onsemi equivalents): 4096-bit Microwire EEPROM, 256 × 16, protect register with PREN/PRREAD/PRWRITE/PRCLEAR/PRDS instructions and PRE pin.
- Philips/NXP 80C552: 80C51 derivative, UART with timer-derived baud rates, 8-channel 10-bit ADC.
Open-source tools referenced
pyserial (BSD), DOSBox-X (GPL), com0com (GPL), socat (GPL), VentMon and PytuTester (inline analyzers for performance verification).