High Speed Modems & the X-Rite 881, 882

Today it is all but impossible to purchase a modem lacking data compression and/or error control protocols. Furthermore most of these require some form of hardware handshake in order to control the flow of data. Many of these advanced features are either unsupported or not required by X-Rite's instruments or software. In order to utilize this newer modem hardware it is necessary to defeat some of their features. On the plus side, in X-Rite's applications, data quantity is limited; thus super speed is not an issue. Further, both the 881 & 882 instruments and the QCLocal & QCNet II software perform their own error correction - modem correction is redundant. Below are listed an assortment of initialization commands that will enable the use of many newer modem types with our products.


Setup strings for High Speed Modems: (>2400 baud):

 US RoboticsHayes CompatibleRockwell (chipset)Microcom/ Motorola
1) disable error correction&M0&Q0\N0\N0
2) disable MNP data compression&K0S46=0%C0%C0
3) enable variable serial port rate&B0&Q0&Q0\J1
4) disable modem flow control&H0&R1&K0&K0\G0
5) disable serial port flow control&I0&K0&K0\Q0


Notes:     Items 1 & 2 are for high speed modems only ( >1200 baud)
Items 3, 4, & 5 are included in the US Robotics &F0 factory preset.
Use S0=0 in the prefix, the rings till answer menu option will override this anyway.

For the US Robotics the prefix would read... S0=0&F0&K0&M0

There is NO "\" character in the prefix editor... instead the "\" character looks like the Japanese Yen symbol - - The letter "T" superimposed over the letter "Y".


v6507 (and higher) Network improvements

Units now support 9600 baud. However, they still default to 2400 baud for compatibility to existing user base of modems. 9600 baud can be selected by going to the "BIT" menu (two middle keys in 'p5'); Press 'p1' until you see "hsmod". Pressing this key toggles to "HSMOD" (High Speed Modem). If lower baud modem is used with HSMOD, unit will drop down to that lower baud. We informally reccomend (and test with) the US-Robotics Sportster (NOT the Sportster SI) 14,400, 28,800 or 33.6K external modem.

Running at 9600 with this modem requires that the network prefix be changed to: "&F0&K0&M0". This setting configures the modem for no CTS/RTS handshaking, and disables data compression and error checking. It is advisable however to run at 2400 baud.

Variable rings-till-answer in auto-answer mode:

This allows unit to answer the phone on the "n'th" ring. Specify "n" by: p3, netwk, cfg, ph, "ring" menu item. Note that the netwk setting in "config" must be set to either "I" (input) or "I&O" (input and output). The default is "answer on first ring". This feature requires the 881-113 cable, or 881-122 Y cable which routes the "ring indicator" line from the modem (connector "B") to pin 5 of the unit.

Variable attempts-to-connect:

(requested by New Zealand folks). This feature sets the number of times ("retries") that the unit will attempt to call after a failed network session (host line busy, etc) To set this feature: p5, netwk, cfg, ph#, "ret" user can select from 0 to 9. Default is 9. (like old software). Improved modem handling for call-in. Old software was unreliable for answering calls at 9600 baud. Added English error warnings. Old software only indicated a "network error number xx". The new software is descriptive, ie: "Host computer offline", etc. Added more allowable characters for phone number and prefixes to support a wider variety of high speed modems.

In Addition:      Dip swiches (if available) for the Sportster should be set to the following:
DTR Override
Verbal Result Codes
Display Result Codes
Auto Answer Off
Carrier Detect Normal
Load Factory Defaults (as opposed to NVRAM)

IF ALL ELSE FAILS, FORCE YOUR MODEM TO CONNECT AT 2400 BAUD. This can be done by the following prefixes in the modem setup string:

 US RoboticsHayes CompatibleRockwell (chipset)Microcom/ Motorola
6) force connection at 2400&N3F5F5%B3

Finally, the US Robotics 14.4 "Sportster SI" modems fall under the Rockwell Type, and will only work reliably if forced to 2400 baud.


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