V.120 Configuration Commands
The following AT commands pertain to V.120 configuration on your DIVA T/A.
AT!E0=n | V.120 N201 Tx (Maximum Transmit Frame Size). N201 Tx (Maximum Transmit Frame | |
| Size) determines the maximum number of octets in an information field to be | |
| transmitted to the remote V.120 device. | |
| Range: 16 to 260. | |
| Default: 260. | |
| Note: If a larger frame needs to be transmitted, the DIVA T/A segments it into V.120 | |
| fragments and expects the remote device to perform reassembly. | |
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AT!E1=n | V.120 N201 Rx (Maximum Receive Frame Size). N201 Rx (Maximum Receive Frame | |
| Size) determines the maximum number of octets in an information field to be received | |
| from the remote V.120 device. | |
| Range: 16 to 260. | |
| Default: 260. | |
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AT!E2=n | V.120 Multiframe Mode. The V.120 protocol supports two different transfer modes | |
| described below: | |
| n=E | Multiframe mode is enabled (default). This mode provides acknowledged |
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| transfers by using Information (I) and acknowledgment (RR/RNR) frames, and |
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| provides error correction and recovery procedures. The link verification |
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| procedure is provided by exchanging SABME and UA frames. |
| n=D | Unacknowledged mode is enabled. This mode uses Unnumbered Information |
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| (UI) frames. The link verification procedure is provided by exchanging XID frames. |
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| The unacknowledged mode is less robust than multiframe mode. |
| Note: The DIVA T/A may automatically switch to the other mode if the link verification | |
| frames issued from the remote device do not match the configured mode on the local | |
| device. The DIVA T/A always prefers the multiframe mode. | |
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AT!E3=n | V.120 K Window Size. Applicable to the multiframe mode only. K (Window Size) | |
| determines the maximum number of sequential data frames that may be outstanding | |
| (not acknowledged) at any given time. | |
| Range: 1 to 127 frames. | |
| Default: 7. | |
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AT!E4=n | V.120 T200 (Retransmission Timer). Applicable to the multiframe mode only. T200 | |
| (Retransmission Timer) is the maximum time allowed to determine if a transmitted | |
| frame was received by the remote device, prior to its retransmission. The unit of | |
| measurement is 1/10 of a second. | |
| Range: 1 to 255. | |
| Default: 15 (equal to 1.5 seconds). | |
| The value specified for T200 (Retransmission Timer) must be less than the value | |
| specified for T203 (Link Integrity Timer) (see “AT!E6=n” on page 43). Otherwise, the | |
| default values are used. | |
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