Re: Zoltrix Modem Driver For Windows 7 Free Download
Leana Eckes
Some time ago someone had a problem using a cheap 14k4 modem (a Zoltrix 14.4 RPI modem) with OS/2. He mentioned a brand that I'd heard of shortly beforehand in another forum. The main problem is that the modem depends on host software for some of its functionality. The modem belongs to a class of modem loosely called "winmodem." Like winprinters, it requires special Windows software and uses host processing capacity to provide function.
After that, the verbal donnybrook started. The owner of the modem took afront, others leaped in offering various explanations and contrary opinions. Many agreed with, "Get a real modem." Others report that they work well.
The problem is that RPI (Rockwell Protocol Interface) modems have part of their firmware implemented as software. It's a cost-cutting measure on the part of the manufacturer, and it may (not always, but sometimes may) introduce some very real software dependencies in a device where no such dependency usually exists (most modems have their firmware completely implemented in hardware and are largely OS-independent).
An RPI modem generally implements some normally-essential code (I think it's mostly support for error correction and data compression) in the driver software instead of on the modem itself. If you don't have the proper driver for the operating system you're running, the modem will sometimes operate in a suboptimal manner, particularly if you're trying to use it on a relatively noisy line. You'll normally see dropped data, which normally manifests itself as CRC errors on Zmodem transfers (or similar packet errors on a PPP connection) and slightly slower file transfer rates.
"Get a real modem" is generally relatively sound advice for RPI modem users if they have problems when using the RPI modem without its drivers and still want to use an operating system not supported by the modem's manufacturers.
Yes, it's possible to get it to work if you have relatively clean phone lines, and I've seen that done. But there are also people who are not in that situation, and in those cases you're essentially out of luck as long as you decide to continue to use that hardware. Without the EC software, connections at 9600 bps and faster can be a real problem on a noisy line. You ain't using 2400 bps where EC wasn't as important.
FWIW, most RPI modems have had a bad reputation for years (I remember threads on FidoNet slamming them about them YEARS ago because of the high numbers of problems being reported on the net at that time). And AFAICT, it's largely a well-deserved bad reputation. The cost savings just isn't worth it if you want to use something other than Windows...
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This document provides a general technical overview of three common types of client modems seen in the field. With a good insight into the hardware issues with modems, you can adjust the client configuration to achieve improved performance.
A controller that provides the identity for the modem. The protocols for hardware error correction, hardware data compression, and basic modulation protocols (for example, V.34, X2, or K56 Flex) exist in the controller. A controller also interprets attention (AT) commands.
Many Internet Service Providers (ISPs) encounter user complaints about unstable connections, low connect speeds and so on. These issues can be caused by client-side, Telco or circuit, or network access server (NAS)-side problems.
In a hardware modem, the modem handles LIU, DSP and CP functions. Hardware modems have historically been the best modems performance-wise, and also the most reliable type. Hardware modems can be external or internal. With external modems, a physical cable (such as an RS-232 serial interface) connects the computer to the modem. In internal hardware modems, the internal bus of the computer handles this function.
The line interface unit (LIU) handles the electronic signaling interface to the Public Switched Telephone Network (PSTN) Network. LIU also encodes and decodes the analog waveform to and from the Pulse Code Modulation (PCM) used in the PSTN.
External hardware modems generally have better diagnostic functionalities for troubleshooting. This is partly because they are quite independent from the computer to which you connect them. Even the least expensive models have a built-in speaker that allows you to detect retrains easily. Lines with increased delay correspond to periods when modems retrained (due to the link quality problems), which is easy to understand (hear) with an external modem, but are not very obvious otherwise.
Most external modems also have LEDs to indicate the status of the connection to the computer, and the activity over the phone line (user data being sent and received). More advanced models have LCDs, and allow you to monitor more details dynamically (such as, the current receive and transmit rates, line noise, error level, signal quality, SNR, compression effectiveness, and so on), as the line condition and data traffic change over time. As a bonus, if the external modem freezes (for example, due to a problem in its firmware), it can be power-cycled without rebooting the computer.
Internal hardware modems usually do not have LEDs. Such modems can use the computer sound card to play the train-up phase, and often rely on the software of the computer to report any details (which makes the results less independent and reliable). Some advantages of internal hardware modems are lower price, and potentially faster data exchange with the computer.
In controllerless modems, CP logic is moved into the computer operating system, while the LIU and DSP are performed on the modem hardware itself. This design is good because the hardware DSP still handles the real-time modulation work, while the computer can handle CPU or memory-intensive data compression function. With good design the difference between hardware and controllerless modems is practically unnoticeable. This is because the CPU performance loss on error correction, and data compression are compensated by data moving more efficiently (with fewer interrupts) between the DSP and the computer.
The HSP design can still be quite effective, if the computer runs an operating system capable of real-time processing. However, most HSP modems are used on computers running Microsoft Windows OS, which is a non-realtime OS. Therefore, HSP modems on Windows computers are often unstable, and experience performance issues, especially when the signal processing functionality competes for CPU cycles with normal computer time-sensitive functions like sound, video and disk drivers operation.
Clients with HSP modems can expect unstable connections as well as performance issues, such as lower speeds, high error rates and so on. A service provider with a high percentage of HSP client modems should expect a higher number of user complaints.
Look at the firmware version to identify whether you use a 56K or V.90 capable modem. In most cases, V1.1 or later is K56Flex and V2.0.65 or later is V.90. The version determines whether the modem is able to make K56Flex or V.90 connections.
Some modem vendors also use V2.0.xx code to integrate K56Flex firmware. For example, Boca has a 2.0.13 K56Flex firmware where 2.0.65 is the V.90 code. This information applies only to some Rockwell clients.
If you are not sure whether your modem is a Rockwell modem, go to the homepage of the vendor to see if the Rockwell label appears. For a list of all modem vendors, see 56K.COM's 56K Modem Manufacturers page.
Users with firmware earlier than 1.1 must upgrade to V.90 (V2.0.65 or later). Firmware versions earlier than 1.1 do not connect at 56KFlex or V.90 and fall back to V.34. Code earlier than 1.1 is also called K56Plus, a pre-K56Flex code that MICA does not support.
If you call a V.90-enabled server, but KFlex connects, add s38=0 in extra settings to disable KFlex. With LT firmware later than 5.12, you can tell whether the handshake attempts V.90. There was a major change to V.90 firmware at 5.12 with the introduction of digital impairment learning (DIL) or "level-learning."
These HSP modems offload both the Controller Process (CP) and the Digital Signal Processor (DSP) functions to the PC. You must have a high speed CPU (200Mhz or better) in order to use these types of modems. For more information, see 56K.COM's Beware Soft Modems article .
In order to determine the type of impairment, call an X2 or V.90-enabled server with a terminal program. After you receive a CONNECT, wait 15 seconds or so and disconnect the call. Then, enter the ATY11 command. The modem responds with a list of frequencies and the receive level of each frequency. Look at the difference between the value reported for 3750 and 3300hz. If this difference is 25 or more, you can infer that there is more than one analog-to-digital conversion or other serious impairment. If the number is close to, but less than 25, you may or may not get a 56 K connection. If you do, the 56 K connection is very poor. A good value for this difference is lower than 18.
Ambient Technologies produces modem telephony chipsets that manufacturers of internal and external modems design into their products. The CL-MD56XX chipset family is a software solution that you can upgrade. The X2 USRobotics technology provides the data rate. See your PC product manufacturer's web site for drivers and support. For more information, see the Ambient Technologies site.
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