NOTE:  It is possible to use an inline splitter to provide the GSP-2900 tip/ring signal to the PBX as well as to a dedicated handset located within the user’s facility.  The splitter would be placed between the GSP-2900 and the PBX.  This configuration is sometimes considered a good contingency plan because, since the dedicated line bypasses the PBX, the dedicated line can be used to make and receive satellite calls even if the PBX fails or even if there is an interruption in the facility power to the PBX.

Loopo Start vs. Ground Start ==>  See the posting http://productsupport.globalstar.com/2008/08/09/fau200-loop-start-no-ground-start/

• Ground Start is a signaling method from a terminal to a switch where one side of a cable pair is temporarily grounded.
• Loop Start supervision is a supervisory signal from an end terminal to a switch in response to completing the loop path.

The Globalstar “fixed phone” products, GSP-2900 and FAU200, support only loop start.

See the following excerpts from the Fixed Phone Compliance Matrix for further details.

7.2.3 Loop Start
7.2.3a The fixed phone shall detect loop start in accordance with BS 6305 and BS 6317.

7.3.1 Additional FAU Features
7.3.1a In addition to the loop calling unguarded clearing protocol that shall be ordinarily provided by the FAU, extra signalling shall be provided in support of this application:· loop current break (clear backwards);· Called Subscriber Answer indication using Line Reversal;· immediate ringing, used instead of ground start to reduce glare (call collision)
7.3.1b Call collision events shall be handled in a manner that gives priority to outgoing phone calls.

7.3.1.1 Clear Backwards
7.3.1.1a When a call is unsuccessful or cleared down by the far end, the fixed phone line interface shall deliver an appropriate tone (as determined by the network) followed by a break of the loop current. The delay from receipt of far end clear indication to loop break, and duration of the break, should be configurable. Enabling the break feature should be configurable.

7.3.3 Loop and Ground Start
7.3.3a The fixed phone shall detect loop start in accordance with BS 6305 and BS 6317.
7.3.3b Ground start support shall not be provided

Keywords:  GSP-2900, RAU, GSP-2800,GSP-2400,FAU200,FAU-200

To see the file, click here ==>

===========================================================
Suggested Filename:gsp-1700-usb-dataport.inf
===========================================================
;------------------------------------------------------------------------------
;  START of the INF File for CDC USB interface to GSP-1700 and GSP-1720
;  Suggested Filename: gsp-1700-usb-dataport.inf
;------------------------------------------------------------------------------
; Windows USB CDC Setup File
; Copyright (c) 2000 Microsoft Corporation

[Version]
Signature="$Windows NT$"
Class=Ports
ClassGuid={4D36E978-E325-11CE-BFC1-08002BE10318}
Provider=%QCOM%
LayoutFile=layout.inf
DriverVer=07/26/2006,0.1

[Manufacturer]
%MFGNAME%=DeviceList

[DestinationDirs]
DefaultDestDir=12 

[SourceDisksFiles]

[SourceDisksNames]           10

[DeviceList]
%DESCRIPTION%=DriverInstall, USB\VID_05C6&PID_3111 

;------------------------------------------------------------------------------
;  Windows 2000/XP Sections
;------------------------------------------------------------------------------

[DriverInstall.nt]
CopyFiles=DriverCopyFiles
AddReg=DriverInstall.nt.AddReg 

[DriverCopyFiles]
usbser.sys,,,0x20

[DriverInstall.nt.AddReg]
HKR,,DevLoader,,*ntkern
HKR,,NTMPDriver,,usbser.sys
HKR,,EnumPropPages32,,"MsPorts.dll,SerialPortPropPageProvider" 

[DriverInstall.nt.Services]
AddService=usbser, 0x00000002, DriverService

[DriverService]
DisplayName=%SERVICE%
ServiceType=1
StartType=3
ErrorControl=1
ServiceBinary=%12%\usbser.sys 

;------------------------------------------------------------------------------
;  String Definitions
;------------------------------------------------------------------------------

[Strings]
QCOM="Qualcomm"
MFGNAME="Qualcomm"
DESCRIPTION="Communications Port"
SERVICE="USB-232 Emulation Driver"
;------------------------------------------------------------------------------
;  END of the USB File
;------------------------------------------------------------------------------

The GSP-1720 can also use its USB interface for data communications, but this capability is rarely used.

PCs which are running Microsoft Windows operating systems will need to use a custom INF file, available here. The INF file instructs Windows XP how to communicate with the GSP-1700 device over USB.

1. Ensure that the GSP-1700 data cable is NOT plugged into the computer.
2. Download the file to a known location on the computer disk. Record the location of the file, because you will need to use this location in the next steps.
3. The file is named with a filename of “.txt” for security reasons.  Rename the file from “.txt” to “.inf” so that Windows will recognize the file as a device driver file.
4. Turn on the GSP-1700.  Insert the GSP-1700 data cable into the GSP-1700 and into the USB port of the computer.   After a slight delay, Microsoft Windows will prompt you for the location of the INF file. Simply navigate to the location where you stored the file (during step 2, above) and press OK.
5. Windows will install the data port driver using standard Windows components.

Note: Apple Mac OS X and Linux operating systems will use their own standard drivers and will NOT need the Microsoft Windows “INF” file.

The pinout is provided in Chapter 8 (page 8-8) of the GSP-1720 Integrator’s reference manual, available HERE.

Specifications, drawings and other details for this part are provided on the Molex web page. http://www.molex.com.   (P/N: 43025-2200)

Molex Part Numbers and Tools:

The following Molex parts are relevant to construction of an interface cable.   Note that Globalstar does NOT sell these parts.  They can be purchased directly from Molex or from electronics suppliers.  The prices shown are approximate, as of April-2007.

• 43025-2200 ==> Molex connector body to mate to the 1720 22-pin port
• 43030-0009 ==> 30 micron gold pins for 20-24 AWG wire, $0.10 each at qty 500
• 63811-1000 ==> Universal Crimp tool for the above-mentioned pins, $50
• 63811-2800 ==> Super Crimper, $215 (alternative to the universal crimp tool)
• 11-03-0043 ==> Pin extraction tool
• 63817-0000 ==> Molex Manual Wire Stripper, $95 (if you don’t have a wire stripper)

These include the FCC Grant, the CE Declaration of Conformity, and many other documents.

Audio levels at the 22-pin connector are as follows:

Audio OUT

• Output impedance = 10 ohms, intended to drive a 16 ohms load
• Freq response = 300 Hz to 3300 Hz
• Output power = 8 mW into 16 ohm full scale out with VDD 2.5 V-2.7 V
• Power Supply rejection ratio = 45 dB

Audio IN

• Input Impedance = 35 Kohms
• Freq response = 300 Hz to 3300 Hz
• Max Input Voltage = 64.5 Vrms

In 2010, we identified the following converters which should work:

http://www.tessco.com/products/displayProductInfo.do?sku=59311&eventPage=1
http://www.sailgb.com/p/alfatronix_voltage_converters/
http://www.roadpro.co.uk/retail/product_level_2.aspx?prod=Voltage+converters
http://www.trcelectronics.com/dc-dc-converters.shtml
http://www.newmarpower.com

In addition, there are a number of DC-DC voltage converters available for different voltage ranges:

http://www.aimtec.com/home

This document applies to the GSP-1700, GSP-1720, GSP-1600, GSP-1620, and GSP-2900.

AT+CFG:

The Globalstar Gateway IWF does not support any useful user configurable +CFG input.

AT+MS:

+MS commands can be used to define the data interface standard (to the PSTN) as follows

• v.21 300bps, full duplex
• v.27ter 4800/2400 bps half duplex
• v.32 9600 bps full duplex
• v.32 bis 14000 bps full duplex
• v.42 error correction
• v.42bis compression/ error correction.

Qualcomm tested several options which successfully configured the IWF to work with a modem. These options were limited by the type of modem and network.

• e.g. to set IWF as v.32 with max and min baud rate fixed at 9600 bps use following command where V32 is the standard, 0 or 1 equals automode on or disabled, 9600 is fixed min rate, 9600 is the fixed max rate.
  • at+MS=V32,0,9600,9600   results in a V32 connection at 9600 bps
  • at+MS=V32,0,4800,4800   results in a V32 connection at 4800 bps
• For V.xx bis the command is entered as follows V1xx
  • at+MS=V132,0,9600,14400,9600,14400                modem connection autobauded back down to 9600

Although V.22 and V.22bis are not stated as being supported by the Gateway IWF, Qualcomm tested the following successfully, as the VOCAL modem (VOCAL Technologies, Inc.) which is used by the IWF, actually supports this standard.   Note …. This has not been fully tested but appears to work.

• at+MS=V22,1              modem connected as V22 at 1200 bps
• at+MS=V122,1    modem connected at V22bis at 2400 bps.

All the above scenarios were able to transfer data at the specified standard.

IMPORTANT NOTE: The +MS command does not provide a response back to the terminal other than OK.  However, it is possible to concatenate the +MS command into a multi-command AT string.  For example:

AT+MS=V122,1;+MS?

will echo back the new +MS string.  This is sometimes useful in automated scripts.