Back-2-Back VIC-2E/Ms?

pitviper

Anyone ever try doing this between 2 gateways? I have some old cards laying around, and this article makes it sound like it's possible using type II and V settings:

E&M Type I - This is the most common interface in North America.
-Type I uses two leads for supervisor signaling: E, and M.
-During inactivity, the E−lead is open and the M−lead is connected to the ground.
-The PBX (that acts as trunk circuit side) connects the M−lead to the battery in order to
indicate the off−hook condition.
-The Cisco router/gateway (signaling unit) connects the E−lead to the ground in order to
indicate the off−hook condition.

E&M Type II - Two signaling nodes can be connected back−to−back.
-Type II uses four leads for supervision signaling: E, M, SB, and SG.
-During inactivity both the E−lead and M−lead are open.
-The PBX (that acts as trunk circuit side) connects the M−lead to the signal battery (SB) lead connected to the battery of the signaling side in order to indicate the off−hook condition.
-The Cisco router / gateway (signaling unit) connects the E−lead to the signal ground (SG)
lead connected to the ground of the trunk circuit side in order to indicate the off−hook
condition.
·
E&M Type III - This is not commonly used in modern systems.
-Type III uses four leads for supervision signaling: E, M, SB, and SG.
-During inactivity, the E−lead is open and the M−lead is set to the ground connected to the SG lead of the signaling side.
-The PBX (that acts as trunk circuit side) disconnects the M−lead from the SG lead and
connects it to the SB lead of the signaling side in order to indicate the off−hook condition.
-The Cisco router / gateway (signaling unit) connects the E−lead to the ground in order to
indicate the off−hook condition.

E&M Type IV - This is not supported by Cisco routers / gateways.

E&M Type V - Type V is symmetrical and allows two signaling nodes to be connected
back−to−back. This is the most common interface type used outside of North America.
-Type V uses two leads for supervisor signaling: E, and M.
-During inactivity the E−lead and M−lead are open.
-The PBX ( that acts as trunk circuit side) connects the M−lead to the ground in order to
indicate the off−hook condition.
-The Cisco router / gateway (signaling unit) connects the E−lead to the ground in order to
indicate off−hook condition.

pitviper

OK, I tried this today between 2 CME routers but no luck – Can’t even seem to find decent documentation, just basic “match the PBX settings” tips.
Tried the following (all using the default wink start signaling):
R1 – E/M(Type II 4-Wire)

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(straight through patch cord)

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E/M(Type II 4-Wire) – R2
R1 – E/M(Type II 4-Wire)

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(T1-xover patch cord)

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E/M(Type II 4-Wire) – R2
R1 – E/M(Type II 4-Wire)

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(straight through patch cord)

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E/M(Type II 4-Wire) TRUNK– R2
R1 – E/M(Type II 4-Wire)

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(T1-xover patch cord)

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E/M(Type II 4-Wire) TRUNK– R2
R1 – E/M(Type II 4-Wire) TRUNK

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(straight through patch cord)

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E/M(Type II 4-Wire) TRUNK– R2
R1 – E/M(Type II 4-Wire) TRUNK

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(T1-xover patch cord)

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E/M(Type II 4-Wire) TRUNK– R2
And then repeated all of the above with Type V, 2-wire settings…nada!

mikej412

Try a rollover cable
Analog E&M Troubleshooting Guidelines (Cisco IOS Platforms) [Gateway Protocols] - Cisco Systems

pitviper

Thanks Mike! Nice find – I haven’t stumbled upon that one yet! I’ll try the rollover cable and see what happens - Sounds like it should work though.

pitviper

The rollover cable works like a charm! No fancy config either – Just need matching E&M type and signaling on both router interfaces. Also noticed that the ports seem flaky after changing settings without doing a shut/no shut.