Description

Tahoe 684 is an 8-wire G.shdsl+ modem with an Ethernet port, the fastest in the Tahoe 68x family. It combines four copper pairs into a single symmetric link with a data rate of up to 22.8 Mbps over a distance of several kilometres.

In addition to the modulations defined in the G.shdsl standard, it supports TCPAM-32, which on the same line gives longer reach and a higher data rate than the standard TCPAM-16.

Operation on four pairs

The modem splits the traffic across the four pairs by itself. Each pair can be set to a different data rate, which is useful when the pairs differ in quality. If one pair stops working, the modem switches to operating on the remaining ones.

Features

Built-in TCP/IP router with a firewall, a DHCP/BOOTP server and VLAN support. Bridge mode, managed or transparent.

Configuration is done from the built-in LCD display and keypad, via the serial console or via telnet. The full list of features is in the Technical data tab.

Several hardware and software watchdogs monitor the device, from basic processor functions to network communication. The metal enclosure is designed for years of continuous operation.

Technical data

Throughput	up to 5.7 Mbps per port up to 22.8 Mbps on a bundled 8-wire line
Standards	G.shdsl, conforms to ITU G.991.2
Interface	Ethernet 10/100 Base-T
Modulation	TCPAM-32 up to 30% higher reach in comparison to HDSL
Features	TCP/IP router NAT/masquerade firewall built-in LCD and keyboard for easy configuration telnet and SSH management SNMP management serial console management DHCP/BOOTP Server DHCP/BOOTP Relay Agent (relaying of the DHCP/BOOTP requests to a central server) firmware upgrade using TFTP managed or unmanaged bridge functionality logging through syslog 802.1q VLAN support inside temperature measurement automatic traffic balancing among four DSL lines individual throughput settings for each line (in case of quality differences between the lines) automatic fall back to 6-, 4- or 2-wire transmission in case of line failure
Processor	Freescale PowerPC 100MHz
Memory	4MB SDRAM
Performance	up to 15,000 packets per second
Network protocols	TCP, IP, UDP, ICMP, TFTP, SNMP, DHCP, BOOTP, PPP, Frame Relay, HDLC, Cisco® HDLC, IEEE 802.1q
WAN encapsulation	ATM AAL5
Dimensions	200 mm (width) x 130 mm (depth) x 45 mm (height)
Power supply	15-30V, 700-350 mA, 11W (110-230V/50-60Hz power supply included)

Reach

Values below were measured on a test line of 0.5mm wire diameter. They depend on an actual line and thus are not guaranteed. They may be different - higher or lower - in an individual case.

Throughput	Reach on 8 wires	Reach on 4 wires	Reach on 2 wires
22784 kbps	2500 m	-	-
16896 kbps	2900 m	-	-
14336 kbps	3200 m	-	-
11392 kbps	3600 m	2500 m	-
6272 kbps	4200 m	3500 m	-
5696 kbps	4700 m	3600 m	2500 m
3072 kbps	5900 m	4100 m	3500 m
2048 kbps	6900 m	5000 m	3900 m
1024 kbps	7500 m	6900 m	5000 m

Additional information

User manual update