Table E.4 is a historical view of the different RAS versions and the modem standard combinations they supported when they were released. Newer RAS versions support all down-level modem compression and error control combinations. The table shows only the most important standard combinations. If there is more than one column for a RAS version, the rightmost column displays the highest modem standards supported by that RAS version.
The leftmost column of that RAS version shows a combination of standards that may occur with less capable modems. For example, the highest modulation rate RAS 1.1a supported at the time of release is V.32 bis; this means it also supports V.32 and V.22 bis which were supported by RAS 1.1 and 1.0. Because this table is only a historical view, it does not reflect that an older RAS version can possibly support a newer modulation standard than is shown in the table. For example, the table shows RAS for Windows for Workgroups 3.11 as supporting only V.32 bis as the highest modulation scheme. This is because V.fc, V.fast, and V.34 modulation scheme modems did not exist yet and therefore were not available for testing. However, RAS for Windows for Workgroups 3.11 may work properly with a V.34 modem in the right configuration. To make it work properly, you may have to use a computer with one or more of the following components:
Table E.4 History of RAS Versions and Supported Modem Standards
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| RAS for Windows for Work-groups version 3.11 |
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Hayes AT, etc. | Hayes AT, etc. | Hayes AT, etc. | Hayes AT, etc. | Hayes AT, etc. | Hayes AT, etc. | ||||||
V.22 bis (2400 bps) and V.32 (9600 bps) | V.32 | V.32 bis (14400 bps) | V.32 bis | Windows NT 3.1: V.fc, V.fast | V.34 | ||||||
Not Supported | MNP4 (may also use V.42) | V.42 with LAPM (may also use MNP4) | V.42 with LAPM (may also use MNP4) | V.42 with LAPM (may also use MNP4) | V.42 with LAPM (may also use MNP4) | ||||||
Not Supported | MNP5 (may also use V.42 bis if V.42 is enabled) | V.42 bis (may also use MNP5 if MNP4 is enabled) | Use RAS data compression along with V.42 bis 1(may also use MNP5 with MNP4 enabled and RAS data compression disabled) | Use RAS data compression along with V.42 bis 1 (may also use MNP5 with MNP4 enabled and RAS data compression disabled) | RAS data compression is automatically used. Enable V.42 bis 1 (may also use MNP5 with MNP4 enabled) | ||||||
*RAS 1.0 and 1.1 were tested only with US Robotics V.32 bis modems at 14400 bps line speed. The modems were configured for V.42, V.42 bis, and V.32 bis. The OS/2 1.3 LAN Manager RAS 1.0 or 1.1 server had an intelligent DigiBoard installed. 1 If an uncompressed file is transmitted between two Microsoft RAS computers, RAS software compression increases throughput significantly more than V.42 bis compression. Do not enable modem compression (MNP5) along with RAS software compression, because it may decrease throughput. | |||||||||||
Note
RAS clients running version 1.0 or 1.1 on the MS-DOS platform should be upgraded to at least RAS version 1.1a, which can be obtained from Microsoft at no charge. RAS server version 1.0 and 1.1 on the OS/2 1.3 platforms were never updated. In general, for RAS 1.x versions on MS-DOS or OS/2 1.3, it is recommended that you upgrade to RAS for Windows for Workgroups 3.11, RAS for Windows 95, or Windows NT 4.0 because of improved performance, new features, and the new, easier-to-use interface.