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Comms Example: GPS Receiver--Cellular Modem--Cellular Phone--Cellular Modem--CPU

GPS Receiver--Cellular Modem--Cellular Phone--Cellular Modem--CPU


  • Cellular modem: ZyXel U-1496P

  • Cellular phone: Motorola SUN 1908AC (no longer in production)

  • Antenna: Directional Yagi antenna

  • CPU: UNIX (Sun OS 2.3)

  • Receiver: Trimble 4000SSi

  • Possible Substitutions (based on site parameters)

  • Cellular modem: Any modem which meets the suggested minimum requirements on our Cellular Modem page.

  • Cellular phone: Since the Motorola SUN 1908AC is no longer supported, we suggest you contact cellular phone companies and describe your needs, or contact the Equipment Services Group (

  • CPU: UNAVCO currently supports UNIX or LINUX systems.

  • Connections

  • 1=Straight serial DB25-25

  • 2=RJ11 phone line to cellular link

  • 3=RJ11 phone line

  • 4=Trimble serial 5 pin or 7 pin null cable (p/n 21295 or p/n 21296)

  • Equipment Configuration

    Cellular Modems

    Local (UNIX) modem:

  • V.32 (4800) protocol

  • 4800 bps DTE speed

  • 10 (characters)N1

  • DSR always on

  • DTR always assumed on

  • CTS/RTS HW flow control

  • v.42 with MNP4

  • Remote modem: as local, except modem set to pick up after one ring.

    Recommended local (at CPU) Zyxel cellular modem register settings:

    Recommended remote (at receiver) Zyxel cellular modem register settings:


    Confirm these settings in the receiver’s CONTROL menu:

  • BAUD RATE/FORMAT: I/O port 1 or 2, 4800 bps, 8-None-1, no HW flow control.

  • REMOTE PROTOCOL: Data Collector Compatible.

  • Download Specifications

    Download software: Trimble Remote Control version 2.201 (15 MAY 1996) for UNIX. All functions of Remote Control software work. Effective receiver file download speed: 4300 bps. [Note: Download rates will vary depending upon site location, local interference, phone line quality, and cellular service.]

    This product is used to perform remote control of 4000SSE/SSi - RC receivers. The programs are available for HP-UX, DOS, SunOS 4.1.x, and Sun Solaris 2.x. The following summarizes the functions and utilities provided by the Remote control programs. Refer to the Trimble Remote Control documentation for details on these programs.

    Function/Utility Program
    Modem link control rconn, rdisconn
    Station/session programming rstation, rsession
    Survey control rsurvey
    Global control rcontrol
    File/download control rfile
    File conversion (r00 to DAT) runpkr00
    Receiver status rstatus
    Receiver reset rreset
    Remote firmware update rupdate
    DAT file naming utility rdatname

    Last modified: 2019-12-27  16:36:35  America/Denver